Figures La Research Articles

The glory that was wrong: el “Chino Malo” approximates Nuyorico

Nicknamed “Chino Malo,” Chinese American painter and art collector Martin Wong's proximity to the Puerto Rican Lower East Side in the 1980s has been under-elaborated and eclipsed to some degree by his collaborations with the Nuyorican literary figurehead Miguel Piñero. By isolating a selection of minor paintings from that legacy – including Chain Saw Heart (Portrait of Joaquin Aganza) (1984), Rapture (1988), and Stanton Near Forsyth Street (1983) – the author contends that a poetics of proximity unfolds through which the national, racial, sexual, and even aesthetic internal orders of Nuyorico are suspended, disturbed, and reframed. The author describes Wong's poetics as a series of persistent queer advances that unsettle Nuyorico's “good” center and develops proximity as a critical alternative to theories of acculturation that hold sway in Latina/o studies. He then figures la maldad signaled by Wong's nickname as an aesthetic posture or attitude. Mal movement or comportment – to defer fear of committing maldades and willfully do things badly, wrongly, or approximately – loosens identity practices from their toil toward completion and full knowing. Grounding the author's analysis across each painting are Wong's signature uses of salvaged, trompe l'oeil, and textual frames through which the artist modulates his lingering in Nuyorico and develops a poetics of proximity.

Agricultural Structural Adjustments to U.S. Policies: Discussion Paper

Chau and de Gorter's paper is focused in the micro-tradition-how do specific price and income policies affect exit/entry, production, and trade. The article is pretty strong on mathematics. However, the graphics greatly clarify the math, and help intuitive thinkers like us. Some further clarification is necessary to show how U.S. policies correspond to the Chau-de Gorter assumptions. First, defining Ps, to be an ad valorem subsidy paid only on the export (over-quota) quantities does not reflect U.S. commodity policies because the U.S. Loan Deficiency Payments are deficiency payments from a fixed price that are paid on all production, not just exports. Nevertheless, their analysis still applies to U.S. LDPs because the critical characteristic of P, is that it is higher than P, at the margin. Secondly, more clarification is needed to establish whether their analysis strictly applies to the U.S. PFCs, Direct Payments, and CounterCyclical Payments. Their theoretical model is derived from analyses involving quotas having in-quota and over-quota prices. In the United States, however, producers get paid the same PFC, Direct Payment, and Counter-Cyclical Payment irrespective of the price they receive or quantity they produce. Hence Chau and de Gorter's subsidy m does not strictly correspond to the PFCs or Direct Payments (which depend on neither) or the Counter-Cyclical Payments (which depend on aggregate season average prices, but not on individual quantities produced). When the subsidy m is paid as a lump sum, both the target price Pd and the base B used to determine m are no longer relevant to producer decision making. Though producers know their own base, and Pd is published; for forward decision making they are both red herrings. First, in both figures la and ib, a rational producer will not produce at any price, P1, less than the minimum of AVC unless he/she perceives m to be conditional on producing B, either in regulation or in production. To do otherwise is to take an avoidable loss on

Self-Assembled Monolayers: Assembling, Disassembling and Reassembling Studies Using Afm

Abstract Self-assembled monolayers (SAM) and multilayers of organic materials have been intensely studied in the past years, due to their numerous potential applications as, for example, lubricants, corrosioninhibitors and/or adhesion-promoters [1,2]. In this talk, we will present results of several studies carried out using Atomic Force Microscopy to investigate octadecylphosphonic acid (OPA) SAM deposited on mica. We have assessed various mechanisms of assembling, disassembling and reassembling the SAM on mica. The SAM deposition method employed in this work was drip coating using an OPA solution. We have used two different solvents, which exhibit very different OPA solubility, in this work: ethanol and trihydrofuran (THF). Regarding the assembling studies, we will show the formation of groups of OPA double-layers as the initial deposition stage (deposition time < 2 seconds) when using ethanol-based solutions. We will also show that annealing such samples at 60°C produces, favorably, OPA quadruple-layers, as shown in figures la and lb, respectively.

Voice-Leading Parsimony in the Music of Alexander Scriabin

Discussions of pitch structure in Scriabin's later oeuvre typically take as their point of departure a description of the mystic chord, a member of set class 6-34. Dahlhaus (1987) describes this chord as a dominant ninth with a flat fifth and an added sixth, whereas others, including Leonid Sabaneyeff (Taruskin 1997, 342), have considered the chord to be generated by the harmonic series, specifically the seventh through thirteenth partials omitting the twelfth. However, since the former supposes a tonal context and the latter ignores context altogether, neither of these descriptions accounts for how this chord is employed in a non-tonal language. A second limitation is that the mystic chord is not the only sonority encountered in Scriabin's music. Instead, there are numerous collections, each of which is closely related to the others by slight alterations of set content. In order to understand the close relation of these collections and their usefulness for Scriabin, it is necessary to determine the properties which bind these collections together, rather than to simply provide an aural description of each collection taken in isolation. The most prominent pitch-class collections in Scriabin's later works are shown in Figure 1. Figure lb reproduces the mystic chord in scalar form. Figures la and Ic share a similar relation to Figure lb. Lowering the A of Figure lb by a half-step to Ab while holding the remaining five

Comparison of Amplification and Imaging Behaviours of Several Gases In The Environmental Sem

Abstract We have investigated the amplification properties of several imaging gases in the Environmental SEM (ESEM) with the intent of forming a set of general guidelines for the selection of gases. In the ElectroScan ESEM, a gas ionisation cascade is used to amplify the secondary electron signals emanating from the specimen surface. The presence of gas in the chamber also gives rise to a pressure dependent background signal derived from ionisation events between gas molecules and high energy primary beam and backscattered electrons. The fraction of secondary electron signal decreases as the pressure is raised. This point is illustrated in figures la and lb which show the calculated fraction of signal contributed by secondary, backscattered, and primary electrons as a function of pressure in helium and water vapour. Helium yields a very pure secondary electron signal over the entire range of pressures shown. Unfortunately, helium does not provide a great deal of signal amplification compared to water vapour (figure 2).

Amniogenesis in Schreiber’s long-fingered batMiniopterus Schreibersii Natalensis

an amnion by folding as described for the tree-tailed bat Tadarida hrasiliensis cynocephala (Stephens 1962). Schreiber's long-fingered bat, Miniopterus schreibersii natalensis, is seasonally monoestrous producing a single off­ spring in November. It has a bicornuate uterus with asymmet­ rically sized horns. The right horn is twice the length of the left one. All implantations occur in the right uterine horn, with 90% of the conceptuses originating from the left ovary (Van der Merwe 1986). Implantation is superficial and the blastocyst expands within the uterine horn. Orientation of the point of initial trophoblastic attachment, like the orientation of the embryonic disc, is anti-mesometrial (Van der Merwe 1982). Soon after the endodermic cells have started to delam­ inate from the inner cell mass during the pre-implantation period, a single cavity, the primitive amniotic cavity, devel­ ops between the remainder of the inner cell mass by means of cavitation (Van der Merwe 1980). However, this cavity as well as its roof (composed of cells of the embryonic mass and overlying trophoblast) do not participate in the formation of the definitive amniotic cavity or definitive amnion respec­ tively. At the stage when the trophoblast covering the embry­ onic pole of the blastocyst starts to proliferate to form the invading syncytiotrophohlast, the floor of the primitive amni­ otic cavity flattens off (Van der Merwe 1982). Owing to this action, the roof of the primitive amniotic cavity, as well as the overlying cytotrophoblast, becomes stretched and progres­ sively thinner until it eventually ruptures and disappears. The embryonic disc at this stage is roofed only by the syncytiotro­ phoblast (Van der Merwe 1982). The purpose of the present study was to determine how the pleuramnion in the superficially implanting Schreibers' long-fingered bat is formed. The main aim was to determine whether the cephaliclhead, lateral and caudal folds develop simultaneously and contribute equally to its formation. There has been some controversy as far as this aspect is concerned because, although authors refer to these folds, some do not elaborate on the contribution made by each of these folds dur­ ing amniogenesis. They normally only mention that the free edges of the folds meet dorsally of the embryo. In the pig these circumferential amniotic folds are in reality all directly continuous with each other (Patten 1948). This, indeed, is expected to be the case in the majority of mammals where a pleuramnion exists. In Schreibers' long-fingered bat these folds eventually become continuous, but this occurs only at a later stage of amniogenesis (see below). Twenty Schreiber's long-fingered bats carrying embryos were collected during July and August at Sandspruit Cave No.1 (24'37'S, 27°40'E) in the northern Transvaal bushveld. Following paraffin-wax embedding, all the genital tracts were serially sectioned at 5 11m and the mounted sections stained:with Ehrlich's haematoxylin and counter-stained with eosin. The sections revealed that upgrowing folds from the peri­ meter of the embryonic disc in Schreiber's long-fingered bat, brought with them ectoderm and extra-embryonic mesoderm (Figures la, b). Because this is a double fold of soma top leur a, the outer part comes into close contact with the syncytiotro­ phoblast. As growth of the folds progresses, the outer layer of the folds eventually covers more of the syncytiotrophoblast overlying the embryonic pole. Finally the folds unite dorsally,

Defects in High Tc Cuprate Superconductors

Characterization of microstructural defects in high critical temperature oxide superconductors has been very valuable in gaining an understanding of their phase transformations and insight into the relationship between defects and some superconducting properties such as critical current densities Jc. For this purpose, transmission electron microscopy (TEM) techniques have been proved powerful. In this article we will briefly summarize typical defects in the perovskite-based layered oxides, i.e., [La(1−x)(Ba,Sr)x]2CuO4, YBa2Cu3O7−δ, and (Bi,Pb)2Sr2Can−1Cun−O4+2n+δ. Then we will discuss the nature of defects in YBa2Cu3O7−δ in detail since this oxide has been most extensively studied. Among the many varieties of microstructural defects in YBa2Cu3O7−δ, we will emphasize only those we consider most important. An account of the field before 1990 is given in an excellent review by Beyers and Shaw and a more recent review of the structure of the grain boundaries in YBa2Cu3O7−δ by Babcock.Since the types and the nature of the defects depend greatly on the crystal structure of the materials, the basic structures of the three oxides are shown in Figures la to 1c: (a) [La1−x(Sr,Ba)x]2CuO4, (2:1:4), (b) YBa2Cu3O7 (1:2:3:), and (c) Bi2Sr2CaCu2O8 (2:2:1:2). (The structure of Tl cuprates are very similar to the Bicuprate and will not be discussed here.)

Sperm passage through the zona pellucida

Sperm passage through the zona pellucida requires the occurrence of the acrosome reaction. This latter reaction, in turn, is supposedly needed to release the acrosomal enzymes, particularly acrosin which has been involved in the sperm binding to and penetration through the zona pellucida. The application of the immunogold technique using the monoclonal antiacrosin antibody ACR-C2E5 allowed us to identify acrosin in hamster, human and guinea-pig spermatozoa at the optic and scanning electron microscope, in which the immunogold labelling was silver enhanced. At the transmition electron microscope the monoclonal antibody was indirectly labelled with 10nm gold particles. In hamster spermatozoa there were three patterns of labelling: a) either no labelling, or an intense one over acrosomal region of apparently acrosome intact spermatozoa (Figures la,b, 2a & 3a); b) an intense labelling over the inner acrosomal surface and on the acrosomal cap of acrosome reacted spermatozoa (Figures lc,d, 2b & 3b); and c) either a slight labelling over the equatorial region or no labelling on acrosome reacted spermatozoa (Figure le,f,2c).

Reconstructions and Dynamic Processes on CdTe Surfaces Studied by UHV High-Resolution Electron Microscopy

Surface profile imaging at resolutions of better than 2Å is highly suitable for studies of surface structures and reactions. In the case of semiconductor materials, the main challenge is to prepare surfaces free of any contamination. The technique has previously been used to study surface reconstructions of Si and CdTe. In our previous observations, clean surfaces of CdTe were obtained by careful control of the incident electron beam within a JEM-4000EX high resolution electron microscope with a pressure of 10-7 torr. In the present study, observations of reconstructions and dynamic phenomena on CdTe surfaces were carried out with a Phillips-430ST, modified for Ultra-High Vacuum in the vicinity of the specimen and equipped with an in situ heating facility. The base vacuum in the region of the sample could usually reach ∼3×l0-9 torr after baking the microscope column at ∼120°C for 36 hours. The CdTe specimen was prepared by cutting a large single crystal into 3mm discs in a [110] direction, then mechanically polishing to a thickness of ∼20 microns, and finally ion milling to perforation.When viewed along a [110] projection, the CdTe sample was found to be dominated by clean or nearly clean (111) and (110) surfaces(with amorphous materials less than 5Å) whilst the (001) surface was usually very short and rough. A completely clean surface was obtained by in situ annealing of the crystal to about 200°. The (110) surface was then found to be reconstructed with a very characteristic chevron appearance in the manner described previously. Long and flat CdTe(OOl) surfaces were obtained by insitu annealing of the crystal at ∼510°C at which temperature edges of the crystal started to gradually sublime. Characterization of the surface structure was then possible when the crystal was cooled back down to temperatures below about 300°C. It was found that the (001) surface had a (2×1) reconstruction at temperatures below about 200°C which transformed reversibly into a (3×1) reconstruction over the approximate temperature range of 200°C<T<300°C. Figures la and lb show the (2×1) and (3×1) reconstructed (001) surfaces, viewed along the [110] projection, which were recorded at temperatures of 140°C and 240°C respectively. Structural models for the (2×1) and (3×1) reconstructions, obtained directly on the basis of the experimental images, are shown in Figs.2a and 2b respectively. The (2×1) reconstruction involves a 1/2 monolayer of Cd vacancies and a very large inward contraction of the remaining Cd surface atoms, which then displace the second layer of Te atoms as indicated. This model is similar to that proposed by Chadi for the Ga-rich (2×1) reconstructed GaAs(100) surface. The (3×1) reconstruction involves both the formation of surface dimers and the presence of vacancies at the surface. Every third atomic-pair is missing along the [1,-1,0] direction, and the remaining two atom pairs at the surface form the surface dimer. Although the (3×1) reconstruction has a larger number of electrons in dangling bonds, a surface with vacancies can be relaxed to reduce the strain energy due to the surface dimers. The directions of the atomic displacements away from the ideal dimer positions are indicated in the figure. Relatively large atomic displacements for several layers into the bulk are clearly visible in experimental images, as seen in Fig.lb. Further details of the surface reconstructions can be found elsewhere.

Effect of titanium addition on a Ni-Al-Co alloy

AEM examinations of a NiAlCo alloy of composition Ni-29 at.% Al-21 at.% Co after room temperature compression show that the microstructure consists of a twinned tetragonal matrix (L10, marked A in Figure 1a) and ordered fcc gamma prime precipitates (L12, marked B in Figure 1a) along grain boundaries. The compressive yield strengths of this alloy at room temperature and 760°C are 754 MPa and 163 MPa respectively. It also has superior room temperature ductility as compared to binary NiAl. An addition of 5 at.% Ti at the expense of Ni was made to this alloy in order to increase the yield strengths. The quarternary alloy shows compressive yield strengths of 976 MPa and 403 MPa at room temperature and 760°C, respectively, indicating that the Ti addition is having the desired effect.Comparison of the microstructures of the two alloys after room temperature compression (Figures la and lb) shows that the Ti containing alloy has a smaller grain size. X-ray diffraction data indicate that the gamma prime volume fraction increases from 10% to 20% as the result of the Ti addition. Titanium was also found to stabilize the B2 matrix (marked A in Figure lb) as no tetragonal L10 phase was found. All precipitates along grain boundaries were identified by micro-diffraction to be gamma prime.

On the Radial Packing of Circles in the Plane

In this article we analyze a method of packing circles in a plane. Two examples of plane-filling patterns constructed with circles of uniform diameter are given in Figures la and lb. The square-packing pattern in Figure la has each circle tangent to four neighboring circles. This pattern constitutes a relatively loose packing compared to the more tightly packed hexagonal-packing pattern of Figure lb, wherein each circle is tangent to six neighboring circles. The packing ratio k is defined as the ratio of the area covered by the circles inside a basic element to the total surface area of that element. A basic element for each packing pattern is shown in Figure 1. Simple calculations give k = it/4 and m/2fi> for the square- and hexagonal-packing patterns, respectively.

Two Museum Houses: A Microanalysis of Cultural Adaptation in the Upper Midwest in the Late Nineteenth Century

6 Two Museum Houses: A Microanalysis of Cultural Adaptation in the Upper Midwest in the Late Nineteenth Century by Reidar Bakken translated by C. A. Clausen The Norwegian Emigrant Museum was established in Oslo in 1952 on the initiative of the Norsemen's Federation (Nordmanns-Forbundet). In 1973 the museum was moved to Hamar, which is centrally located for the two great emigration counties (fylker) of Oppland and Hedmark. The greater part of the museum consists of archives and microfilm copies of important source material, especially from the United States, but it also has a collection of objects and several buildings from the upper Midwest. The museum is being expanded as regards both collection and staff and in 1988 was given the official name of The Norwegian Emigrant Museum (Norsk U tvandrermuseum) . In this article attention will be focused on the two dwelling houses which are located in the open-air division of the museum. The first house acquired by the Emigrant Museum was built in the year 1871 at Norman, North Dakota, by Per Bârderud from Grue, Solor. This dwelling has become accepted by people in Norway as the standard NorwegianAmerican house. (Figures la and b). At Grue the house is still standing which the Bârderud family left in 1870. It is being maintained by the Gruetun Museum at Kirkenaer. By a trip of an hour and a half between Kirkenaer and Hamar one can thus 119 120 Reidar Bakken Fig. la. Borderud house at the Norwegian Emigrant Museum. The house was built in Norman, North Dakota, in 1871, by Peder Borderud from Grue in Soler. Courtesy Hedmark Museum. follow an emigrant family from the home milieu in the old country to their new life in America (Figure 2). The other building is usually called the Gunderson house in honor of the man who built it, the cotter Knut Gunderson from Krodsherad in Buskerud (Figure 3). The house was erected near Vining, Otter Tail county, Minnesota, and the documents which came with the house to Norway state that it was built in 1 883 . 1 This date has been repeated in later historical literature.2 The facts of Knut Gunderson's career, however , suggest that this dating must be revised. In Krodsherad the cotter's dwelling which the Gunderson family left is also preserved (Figure 4). It is in a very bad state of repair; but, with the aid of the Emigrant Museum, work is in progress to assure its future. Thus, here also is an opportunity to compare an emigrant's way of life in Norway and in America. For the Emigrant Museum the most important question is: what happened to Norwegian emigrants, culturally speaking , in their new homeland? The emigrants carried Nor- Two Museum Houses 121 Fig. lb. Scale drawing of Borderud house by Are Vesterlid. wegian folk culture to a foreign land; and the development of a Norwegian-American folk culture forms a part of Norwegian cultural history which the Museum desires to document , investigate, and make known. What can these two houses tell about this subject? It is the dissimilarities between the Norwegian and the American houses which immediately attract attention. Were so few Norwegian traditions carried along to America? Or are the American houses possibly more Norwegian than at first glance they appear to be? Here is a debate which has long occupied American architecture students. TWO THEORIES IN AMERICA In considering American log houses ( lafiehus ) and their relationship to building customs in Europe, one has to deal with two contradictory theories. C. A. Weslager, who has under- 122 Reidar Bakken Fig. 2. The main building on the Bàrderud farm in Grue. The house was probably built toward the end of the eighteenth century. Photograph by Birger Nesholen. taken detailed studies of American log houses during the pioneer era, maintains that during the post-pioneer period it is absolutely impossible to designate a log house in national terms. He argues that the log houses underwent a development in America which turned them into distinctive American cultural products, even though they had European roots.3 He further maintains that it is not possible to select specific elements and say, for example, that...

Tribobreakdown in glasses induced by subthreshold high-intensity radiation

In the experiments we used the procedure for determining the emission of electromagnetic waves presented in [6], in which the signals are measured to within 0.i mV. The experiments were performed with careful shielding of the samples from external signals. The high-intensity radiation (% = 1.06 units, T ~ 10 -3 and 3"i0 -s sec) with different intensity acted on the sample placed in a metallic jacket. Electromagnetic signals (noise) from the light interaction were not recorded, which was monitored by tests: without and with a sample, but no fracturing (the sample was additionally shielded). A sample with a mechanical break was also placed in the same jacket the entire mechanical action system was carefully shielded. The samples consisted of K-8 silicate glass with dimensions of i  1  5 cm, organic glass (polymethyl methacrylate -- PMMA) with dimensions 1 x 1 x 3 cm, and colorless quartz with dimensions of 1.5 x 1.5 x 2 cm. The radiation was focused inside the samples by a lens with a focal length F = 5 cm. The radiation intensity (I) wasequal to0.1, 0.3,0,5, 0.7,0.9, 1.5,2 Ith(with one-time action of threshold radiation with I = Ip single mechanical fractures with minimum dimensions of ~50-i00 ~m appear). At least 20 experiments were performed for each type of sample and value of E. Figures la and 2a show the measurements of the electromagnetic signals (EMS), which appear with "purely mechanical" fracture of the PPM and K-8 glass samples. The maximum magnitude of the EMS in the experiments is equal to 30-40 mV. In the presence of fracturing (motion of the crack) new free surfaces, on which charge is located and the field of the charge is sufficient to breakdown the gas filling the space between the surfaces being formed, are constantly forming [7, 8]. Thus, it can be conjectured that the EMS recorded is produced by tribobreakdown accompanying the mechanical fracturing of the samples. Figures la and 2a contain an entire series of separate spikes-signals, which can be attributed to the appearance of a series of cracks: new cracks appear in front of the main cracks [9]. Judging from the duration of the EMS, the time for the motion of the cracks is equal to ~i0 -2 sec in PMMA and ~2"i0 -3 sec in K-8 glass, which is an entirely reasonable value. In fracturing the K-8 glass samples, we made a cut on their surfaces, which probably encourages the forward motion of the crack.

The Strain Dependent Accommodation Behaviour of Extrinsic Grain Boundary Dislocations

Previous work on a fully austenitic stainless steel has shown that the nucleation and growth of Niobium Carbide (NbC) particles at grain boundaries can be substantially affected by deformation introduced prior to ageing (1). The present investigation which is, in part, an extension of the above work was instigated to examine the accommodation behaviour of extrinsic grain boundary dislocations as a function of deformation and temperature. The alloy investigated contained 20% chromium, 25% nickel, 0.6% niobium, 0.02% carbon + nitrogen, balance iron. Solution treated specimen material was cold rolled by 2%, 5% and 13% prior to annealing for times between 5 and 15 minutes at temperatures ranging from 650°C to 1000°C.Figures la and b show typical grain boundaries in the as-worked 2% and 5% materials; extrinsic dislocations appearing as linear features in the grain boundaries. However, grain boundaries in specimen material deformed by 13% contained such large numbers of these defects that the clear resolution of the individual dislocations was frequently impossible.

Discussion of: The Use of Gradients to Aid in the Interpretation of Mixture Response Surfaces

In the majority of the problems I encounter the level of the response is of primary interest. In this situation I believe plots of the predicted responses along the component axes are more informative than the gradient plots. The predicted response plots contain information on both the level and slope of the surface, while the gradient plot provides no information on the level of the response. To illustrate this point let's consider the predicted response plot for Kurotori's data shown in Figure la and the corresponding gradient plot shown in Figure lb (Cornell and Ott's Figure 8b). In both Figures la and lb we see that component x3 has the larger curvature along its component axis. Components x2' and xl' have similar curvature but to a lesser extent. We also see that responses of 3000 or larger are predicted at the centroid of the region and along the component axes in the neighborhood of xi' = .2, X2' = X3' = .4 and 3,' = .5, xl' = x2 = .25. We are reminded that the stated objective of Kurotori's study was to find a composition with an elasticity (y) > 3000. Figure la, the response surface contour plot, and an examination of the raw data all indicate that this objective can be met. Before leaving this example we should point out that the gradient plot enables one to find the points on the component axes where the slopes change direction (ie, inflection points) more easily than the predicted response plot. However, after examining the predicted response plot one wonders whether such a small effect is of any practical importance.

Altered Cell Microfibrillar Orientation in Ethylene-treated Pisum sativum Stems

Altered Cell Microfibrillar Orientation in Ethylene-treated <i>Pisum sativum</i> Stems

Studies in cyclic polymerization and copolymerization—VI. The synthesis and cyclic polymerization of aromatic divinylacetals and divinylfurfural

WE HAVE shown previously that when aliphatic divinylacetals are polymerized in the presence of free-radical initiators intramolecular eyclization and intermolecular chain growth occur simultaneously with the formation of polyvinylacetals [1]. The study of the cyclic polymerization of aromatic divinytacetals was also of interest. We have already discussed the properties and tendency to undergo cyclic polymerization of the first representative of this class of compounds, divinylbenzal [2]. The synthesis and polymerization of divinyl-(2-methyl)benzal, divinyl-(4methyl)benzal and divinylfurfural are described in this paper and details of the preparation of polydivinylbenza] are also given. The synthesis of the monomers was similar to that of the aliphatic divinylacetals, in which two molecules of hydrogen chloride are abstracted from the #, fi'-diehlorodiethyl acetals. Dehydroehlorination was carried out in vacuo (70-100 ram) at 180-240 ° by means of granular potassium hydroxide. The dichloroacetals were prepared by reacting the aromatic aldehydes or furfural with ethylene chlorohydrin or tetra-p-chloroethoxysilane in the presence of acid catalysts. The constants of the divinylacetals obtained are given in Table 1, where the properties of divinylbenzal are also given for comparison. The acetals are eolourless liquids with a characteristic odour, distilling in vacuo without decomposition and without significant polymerization. The ability of these monomers to undergo cyclic polymerization was studied by po]ymerizing them in bulk with benzoyl peroxide or azcbisisobutyronitr f le . Data on the dependence of the degree of conversion on the time and temperature of polymerization, and also on the concentration and nature of the initiator, are given in Figures la and b a n d in Table 2. I t is seen from these results that the curves of the kinetics of polymerization of the aromatic divinylacetals are similar to those of divinylfur£ural butthere are definite dff-

Isolation of an Unpigmented Skin Reactive Constituent from Extracts of Ragweed Pollen by Electrophoresis.

In 1938 experiments were undertaken, using a conventional moving boundary technique, to separate the fractions and to determine the electrical charge of the constituents of giant ragweed pollen extracts. At that time it was observed that the pigments in dialyzed ragweed extracts at pH 7.0 were negatively charged. The results during that summer and the succeeding winter, however, were contradictory, because the relation of the pigments to the biologically active constituents was uncertain.Using the Tiselius1 cell for the study of the moving boundaries of protein solutions and the Philpot-Svensson2 technic to analyze the quantity and nature of the constituents, further progress may now be reported. Figures la and 1 b are illustrations of the type of curves given by the major constituent. This major constituent is negatively charged, slow moving, unpigmented, and highly skin reactive in persons sensitive to ragweed. A minor constituent, about 1/5 that of the unpigmented major constituent, appearing in the pi...

THE EXPRESSION OF MENDELIAN FACTORS IN THE GAMETOPHYTE OF MAIZE

Page 425, line 6, for "C. N. Collins" read "G. N. Collins." Page 428, line 10, for "was found to 41.5" read "was found to be 41.5." Page 430, line 2, for "17 plants" read "17 virescent plants." Page 451, line 10 from bottom, for "figures la and lb" read "figures 1a and 1b

THE EXPRESSION OF MENDELIAN FACTORS IN THE GAMETOPHYTE OF MAIZE

Page 425, line 6, for C. N. Collins read G. N. Collins. Page 428, line 10, for was found to 41.5 read was found to be 41.5. Page 430, line 2, for 17 plants read 17 virescent plants. Page 451, line 10 from bottom, for figures la and lb read figures 1a and 1b