Major Functional Types Research Articles

Microscale is key to model current and future Maritime Antarctic vegetation

Despite being one of the most pristine regions in the world, Antarctica is currently also one of the most vulnerable to climate change. Antarctic vegetation comprises mostly lichens and bryophytes, complemented in some milder regions of Maritime Antarctica by two vascular plant species. Shifts in the spatial patterns of these three main vegetation groups have already been observed in response to climate change, highlighting the urgent need for the development of comprehensive large-scale ecological models of the effects of climate change.Besides climate, Antarctic terrestrial vegetation is also strongly influenced by non-climatic microscale conditions related to abiotic and biotic factors. Nevertheless, the quantification of their importance in determining vegetation patterns remains unclear. The objective of this work was to quantify the importance of abiotic and biotic microscale conditions in determining the spatial cover patterns of the major functional types, lichens, vascular plants and bryophytes, explicitly determining the likely confinement of each functional type to the microscale conditions, i.e., their ecological niche.Microscale explained >60 % of the spatial variation of lichens and bryophytes and 30 % of vascular plants, with the niche analysis suggesting that each of the three functional types may be likely confined to specific microscale conditions in the studied gradient. Models indicate that the main microscale ecological filters are abiotic but show the potential benefits of including biotic variables and point to the need for further clarification of vegetation biotic interactions' role in these ecosystems. Altogether, these results point to the need for the inclusion of microscale drivers in ecological models to track and forecast climate change effects, as they are crucial to explain present vegetation patterns in response to climate, and for the interpretation of ecological model results under a climate change perspective.

Upscaling dryland carbon and water fluxes with artificial neural networks of optical, thermal, and microwave satellite remote sensing

Abstract. Earth's drylands are home to more than two billion people, provide key ecosystem services, and exert a large influence on the trends and variability in Earth's carbon cycle. However, modeling dryland carbon and water fluxes with remote sensing suffers from unique challenges not typically encountered in mesic systems, particularly in capturing soil moisture stress. Here, we develop and evaluate an approach for the joint modeling of dryland gross primary production (GPP), net ecosystem exchange (NEE), and evapotranspiration (ET) in the western United States (US) using a suite of AmeriFlux eddy covariance sites spanning major functional types and aridity regimes. We use artificial neural networks (ANNs) to predict dryland ecosystem fluxes by fusing optical vegetation indices, multitemporal thermal observations, and microwave soil moisture and temperature retrievals from the Soil Moisture Active Passive (SMAP) sensor. Our new dryland ANN (DrylANNd) carbon and water flux model explains more than 70 % of monthly variance in GPP and ET, improving upon existing MODIS GPP and ET estimates at most dryland eddy covariance sites. DrylANNd predictions of NEE were considerably worse than its predictions of GPP and ET likely because soil and plant respiratory processes are largely invisible to satellite sensors. Optical vegetation indices, particularly the normalized difference vegetation index (NDVI) and near-infrared reflectance of vegetation (NIRv), were generally the most important variables contributing to model skill. However, daytime and nighttime land surface temperatures and SMAP soil moisture and soil temperature also contributed to model skill, with SMAP especially improving model predictions of shrubland, grassland, and savanna fluxes and land surface temperatures improving predictions in evergreen needleleaf forests. Our results show that a combination of optical vegetation indices and thermal infrared and microwave observations can substantially improve estimates of carbon and water fluxes in drylands, potentially providing the means to better monitor vegetation function and ecosystem services in these important regions that are undergoing rapid hydroclimatic change.

Contributed Session II: Motion/direction-sensitive thalamic neurons project extensively to the middle layers of primary visual cortex

The motion/direction-sensitive and location-sensitive neurons are two major functional types in mouse visual thalamus that project to the primary visual cortex (V1). It has been proposed that the motion/direction-sensitive neurons mainly target the superficial layers in V1, in contrast to the location-sensitive neurons which mainly target the middle layers. Here, by imaging calcium activities of motion/direction-sensitive and location-sensitive axons in V1, we find no evidence for these cell-type specific laminar biases at population level. Furthermore, using a novel approach to reconstruct single-axon structures with identified in vivo response types, we show that, at single-axon level, the motion/direction-sensitive axons have middle layer preferences and project more densely to the middle layers than the location-sensitive axons. Overall, our results demonstrate that Motion/direction-sensitive thalamic neurons project extensively to the middle layers of V1, challenging the current view of the thalamocortical organizations in the mouse visual system.

Laminar distribution and arbor density of two functional classes of thalamic inputs to primary visual cortex

SUMMARYMotion/direction-sensitive and location-sensitive neurons are the two major functional types in mouse visual thalamus that project to the primary visual cortex (V1). It is under debate whether motion/direction-sensitive inputs preferentially target the superficial layers in V1, as opposed to the location-sensitive inputs, which preferentially target the middle layers. Here, by using calcium imaging to measure the activity of motion/direction-sensitive and location-sensitive axons in V1, we find evidence against these cell-type-specific laminar biases at the population level. Furthermore, using an approach to reconstruct axon arbors with identified in vivo response types, we show that, at the single-axon level, the motion/direction-sensitive axons project more densely to the middle layers than the location-sensitive axons. Overall, our results demonstrate that motion/direction-sensitive thalamic neurons project extensively to the middle layers of V1 at both the population and single-cell levels, providing further insight into the organization of thalamocortical projection in the mouse visual system.

Metabolic Functions of G Protein-Coupled Receptors and β-Arrestin-Mediated Signaling Pathways in the Pathophysiology of Type 2 Diabetes and Obesity.

Seven transmembrane receptors (7TMRs), often termed G protein-coupled receptors (GPCRs), are the most common target of therapeutic drugs used today. Many studies suggest that distinct members of the GPCR superfamily represent potential targets for the treatment of various metabolic disorders including obesity and type 2 diabetes (T2D). GPCRs typically activate different classes of heterotrimeric G proteins, which can be subgrouped into four major functional types: Gαs, Gαi, Gαq/11, and G12/13, in response to agonist binding. Accumulating evidence suggests that GPCRs can also initiate β-arrestin-dependent, G protein-independent signaling. Thus, the physiological outcome of activating a certain GPCR in a particular tissue may also be modulated by β-arrestin-dependent, but G protein-independent signaling pathways. In this review, we will focus on the role of G protein- and β-arrestin-dependent signaling pathways in the development of obesity and T2D-related metabolic disorders.

СТРУКТУРНО-КОМПОЗИЦІЙНІ ОСОБЛИВОСТІ АНГЛІЙСЬКОГО ПРОФЕСІЙНО ОРІЄНТОВАНОГО ДІАЛОГІЧНОГО МОВЛЕННЯ МАЙБУТНІХ ЛІКАРІВ

Background. English professionally oriented dialogue is an integral part of medical professional sphere. It is closely connected to professional responsibilities and professional competence in medicine. English professionally oriented medical dialogue is a complex, multi-faceted process of workplace communication between a doctor and a patient arising from the needs of professional medical practice. It includes perception and understanding of the patient’s needs, information analysis and specific professional interaction between physicians and patients. Purpose. The current paper aims to analyze structural and compositional characteristics of English professionally oriented dialogue of prospective physicians as well as to classify main functional types of dialogues according to phases of the medical consultation. Results. While carrying out the research, the author analyzed more than 150 professional dialogues and authentic audiovisual fragments to select 50 of them for training purposes. The samples correlated with major functional types of workplace dialogues and became the basis for teaching professionally oriented interaction to students majoring in Medicine. Instruction is arranged in such a way that teaching functional dialogic communication (information-seeking and negotiation dialogues) follows the main structural phases of medical consultation. The major structural elements of the medical consultation include: contact, orientation, argumentation, corrective phase. In the course of training, special attention was also given to language aspects of professional dialogues of physicians. Discussion. Developed materials are open to improve the quality of educational programs, manuals and textbooks for future physicians as additional prospects at medical higher education institutions.

Adaptive variation in vein placement underpins diversity in a major Neotropical plant radiation

Vein placement has been hypothesised to control leaf hydraulic properties, but the ecophysiological significance of variation in vein placement in the angiosperms has remained poorly understood. The highly diverse Neotropical Bromeliaceae offers an excellent system for exploring understudied relationships between leaf vein placement, physiological functions, and species ecology. To test key hypotheses regarding the links between vein placement, functional type divergences, and ecological diversity in the Bromeliaceae, I characterised the ratio of interveinal distance (IVD) to vein-epidermis distance (VED) in 376 species, representing all major functional types and 10% of the species diversity in the family, as well as bioclimatic properties and key leaf traits for subsets of species. There were significant differences in vein placement parameters in species of contrasting functional type, habitat association, and bioclimatic distribution. In many C3 tank-epiphytes, a greater ratio between interveinal distance and the depth of veins within the mesophyll reflects optimisation for resource foraging in shady, humid habitats. In succulent terrestrials, overinvestment in veins probably facilitates rapid recharge of water storage tissue, as well as restricting water loss. These results highlight how divergences in vein placement relate to distinctive ecophysiological strategies between and within bromeliad functional types, and provide timely insights into how structural–functional innovation has impacted the evolution of ecological diversity in a major radiation of tropical herbaceous angiosperms.

Different biomechanical design and ecophysiological strategies in juveniles of two liana species with contrasting growth habit

• Premise of the study: Lianas constitute a major functional type in tropical zones. While some liana species start climbing immediately after germination (shade-avoidance), others have a long self-supporting phase (shade-tolerance). The morphophysiological characteristics of these two growth habits are unknown.• Methods: We quantified growth traits, biomass allocation, mechanics, anatomy, and hydraulics for saplings of Ventilago calyculata (an immediate obligate climber) and Ziziphus attopensis (having a long self-supporting phase), both in the family Rhamnaceae. The mechanics, anatomy, and hydraulics for the mature individuals of the two species were also evaluated.• Key results: In the juvenile stage, V. calyculata had a higher slenderness ratio, height growth rate, and photosynthetic rate but similar biomass growth rate compared with Z. attopensis. In contrast, Z. attopensis had a higher leaf area growth rate, specific leaf area, and leaf mass fraction. Ziziphus attopensis had stiffer, but less conductive stems than V. calyculata. Stem rigidity of saplings decreased from base to apex in Z. attopensis, but increased in V. calyculata. Both species had similar resistance to xylem embolism. However, the leaves of V. calyculata were able to resist greater water deficits. At the mature stage, wider and longer vessels emerged in the xylem, and both species increased stem specific conductivity and drought resistance in stems and leaves. Ventilago calyculata had significantly higher specific conductivity and was more drought tolerant than Z. attopensis.• Conclusions: The two lianas differed significantly in growth, biomass allocation, anatomy, mechanics, ecophysiology, and hydraulic properties in line with their growth habits and shade adaptation strategies.

Plant functional types in Brazilian savannas: The niche partitioning between herbaceous and woody species

An essential characteristic of savannas is the presence of two main plant functional types: grasses and trees. The tree–grass coexistence in savannas is expected to be stabilised either deterministically by water availability or by occurrences of fire and herbivory. However, under a neutral macroevolutionary perspective, functional types could arise purely as a consequence of branching processes in plant lineages. We sought plant functional types in cerrado by assessing 360 species and 11 functional traits that correspond to important dimensions of the niche of plants. Then, we tested whether random branching processes in plant lineages could generate the observed plant functional types. We sought functional types with the k -means partitioning analysis. We constructed a phylogenetic tree for all species sampled and tested whether the phylogeny could be generated by one of the branching processes that can randomly produce functional types: (1) pure birth, (2) rate-constant birth–death, and (3) rate-variable birth–death models. Then, we compared the functional types we observed with a multivariate analysis of variance in a phylogenetic context. Two major functional types characterised the cerrado plant community – one type dominated by grasses and herbaceous shrubs and other by woody shrubs and trees. These functional types were different from the functional types simulated under Brownian motion of evolution of traits. Thus, underlying adaptive processes rather than random evolutionary processes accounted for the plant functional types. The herbaceous and woody functional types seem to have appeared as a consequence of adaptive processes of plants to cope mainly with water availability, fire, and herbivory. However, the niche partition between herbaceous and woody species supports that the reduction in the competitive interactions may be also important to the stable coexistence between trees and grass in savannas.

Water use efficiency and drought survival in Mediterranean perennial forage grasses

In Mediterranean areas, water use efficiency (WUE) is mainly increased by maximising crop growth during the rainy seasons. Perennial forage species have a number of advantages in comparison to the predominantly used annuals. They can utilize water from autumn to spring, while annuals need to be sown or to germinate from the soil seed bank. Under Mediterranean annual rainfall pattern, perennial plants must grow from autumn to spring and survive under summer aridity. Drought survival can impact water use efficiency through plant mortality and stand recovery after autumn rainfalls. In order to enhance knowledge of physiological and agronomic traits associated with WUE and persistence, a 3-year study was conducted at two Mediterranean sites, comparing a range of accessions of two perennial species, cocksfoot ( Dactylis glomerata L.) and tall fescue ( Lolium arundinaceum (Schreb.) Darbysh). Within the accessions of predominantly Mediterranean origin, we defined four major functional types, i.e. groups of accessions with similar response to summer drought. One type (FT1) is represented by the only cultivar of a semi-arid cocksfoot (Kasbah) that is completely summer dormant, with high persistence under the most arid situations but with low WUE. The type FT2 all cocksfoot cultivars (Currie, Delta-1, Jana, Medly, and Ottava) that are not or less summer dormant, with good perenniality and intermediate productivity at rainy seasons. The type FT3 includes the cultivars of tall fescue (Centurion, Flecha, Fraydo, and Tanit) that combine an incomplete summer dormancy, a deep rooting system and the highest WUE from autumn to spring. The type FT4 is represented by a cultivar of tall fescue (Sisa) with no summer dormancy, therefore less persistent and also less productive. Dehydration avoidance in tall fescue and cocksfoot and summer dormancy in cocksfoot were the main strategies contributing to persistence under summer drought. WUE in autumn was highly correlated with sward recovery after drought. Seasonal and total WUE were also highly correlated with biomass production over the same period and with depth and density of the root system. Parameterization of functional types of the major species of forage grasses will enhance future modelling work to test the effects of a range of environments and future climate scenarios.

Sensing the fullness of the bladder

Mechanosensory transduction participates in vital physiological functions such as control of blood pressure, food intake and micturition. Within the urinary tract, electrical impulses in bladder afferent fibres encode the fullness (volume and/or pressure) of the bladder; the information is conveyed via the pelvic and hypogastric nerves to the central neuronal circuits which in turn generate efferent nerve activity to drive coordinated activity of detrusor contraction and urethral sphincter relaxation that initiate evacuation (de Groat, 2006). Extensive efforts have been devoted in recent years to investigate the mechanisms that control bladder afferent activity in normal and in pathological conditions. Despite of the various progresses reported in the literature, the fundamental question of how mechanical force is transduced into afferent discharges remains largely unresolved. It has long been hypothesized that mechanosensory transduction relies on mechanically gated ion channels expressed on afferent terminals. Studies in C. elegans and Drosophila have identified three classes of putative mechanosensory transduction molecules: the degenerin/ENaC/ASIC channels, the transient receptor potential (TRP) cation channels and the two-pore-domain K+ channels (Chalfie, 2009). However, little information is currently available as to whether these channels, except for TRPV1 (Birder et al. 2002; Daly et al. 2007), participate in mechanosensory transduction in the urinary bladder. On the other hand, there has also been increasing interest in the putative sensory role of the urothelial (and other non-neuronal) cells, which have been shown to express a range of putative ‘sensory molecules’ and to release chemical mediators such as ATP, NO and prostanoids in response to mechanical and chemical stimulations (Birder, 2005). These mediators may in turn interact with receptors on afferent terminals to activate afferents or to modulate afferent excitability. In an article in this issue of The Journal of Physiology, Zagorodnyuk et al. (2009) employed a flat-sheet guinea pig bladder preparation to study the mechanosensory responses of bladder afferents by ‘close-to-target’ extracellular recordings. They had previously identified five major functional types of bladder afferents in this species (Zagorodnyuk et al. 2006, 2007) and here they focused on two types of bladder afferents with receptive fields in the vicinity of the urothelium. They examined the effects of degenerin/ENaC/ASIC channel blockers on the responses of muscular-mucosal and mucosal high-responding afferents to muscle stretch and/or mucosal stroking. Amiloride (100 μm) was ineffective, whilst remarkably, benzamil attenuated stretch- and/or stroking-induced afferent discharges in a concentration-dependent manner with 300 μm benzamil virtually abolishing stretch-induced responses. Stretch-activated channel blockers (gadolinium and SKF96365), on the other hand, were without effect on the mechanosensory responses. Furthermore, they showed that mechanosensory responses in these fibres were unaltered in the presence of a purinergic antagonist pyridoxal phosphate 6-azophenyl-2′,4′-disulfonic acid (PPADS) or when calcium-dependent vesicle release of chemical mediators was blocked. The authors concluded that mechanosensory transduction in muscle-mucosal and mucosal high-responding fibres does not rely on Ca2+-dependent vesicle release of chemical mediators such as ATP. Instead, benzamil-sensitive stretch-activated ion channels are likely to mediate mechanosensory transduction by receptive terminals. If they are right, these findings may represent an important step towards eventually delineating the molecular mechanisms of mechanosensory transduction in the urinary bladder. Conceivably, the search for mechanosensory transduction molecules can be narrowed down to the benzamil-sensitive degenerin/ENaC/ASIC channel family, some of which are known to be expressed in the urothelium, the detrusor muscle and the afferent terminals. Nevertheless, considering that relatively high concentrations of benzamil were needed to block the mechanosensory activity in the guinea pig bladder, further studies using more potent and selective pharmacological tools, with other species as well as transgenic animals, should be warranted. It may be worth pointing out that the finding that Ca2+ free perfusion did not affect mechanosensory activity in the guinea pig bladder does not necessarily preclude a sensory role of non-neuronal cells in other conditions. Rather, the data at best imply that non-neuronal release of mediators may not be sufficient to exert significant effects on afferent terminals in such experimental condition. Indeed, there has been plenty of experimental data indicating that the urothelial contribution to mechanosensory activity may be up-regulated in pathological conditions. Moreover, the use of Ca2+ free perfusion may not be sufficient to block potential intercellular communication between primary afferents and non-neuronal cells via exchange of second messenger molecules through gap junctions, as has been demonstrated by Ennes et al. (1999) for DRG and colonic myocytes co-cultured in vitro. An exciting new development in the field of mechanotransduction in vascular smooth muscles has been the findings that several Gq-coupled GPCRs can be activated by membrane stretch, leading to the activation of certain TRP channels via the phospholipase C (PLC) pathway (Voets & Nilius, 2009). It will be interesting to investigate whether a similar GPCR–TRP channel interaction mediates mechanosensory transduction in the urinary bladder.

Tissue-specific transcription factors in progression of epithelial tumors

Dedifferentiation and epithelial-mesenchymal transition are important steps in epithelial tumor progression. A central role in the control of functional and morphological properties of different cell types is attributed to tissue-specific transcription factors which form regulatory cascades that define specification and differentiation of epithelial cells during embryonic development. The main principles of the action of such regulatory systems are reviewed on an example of a network of hepatocyte nuclear factors (HNFs) which play a key role in establishment and maintenance of hepatocytes--the major functional type of liver cells. HNFs, described as proteins binding to promoters of most hepatospecific genes, not only control expression of functional liver genes, but are also involved in regulation of proliferation, morphogenesis, and detoxification processes. One of the central components of the hepatospecific regulatory network is nuclear receptor HNF4alpha. Derangement of the expression of this gene is associated with progression of rodent and human hepatocellular carcinomas (HCCs) and contributes to increase of proliferation, loss of epithelial morphology, and dedifferentiation. Dysfunction of HNF4alpha during HCC progression can be either caused by structural changes of this gene or occurs due to modification of up-stream regulatory signaling pathways. Investigations preformed on a model system of the mouse one-step HCC progression have shown that the restoration of HNF4alpha function in dedifferentiated cells causes partial reversion of malignant phenotype both in vitro and in vivo. Derangement of HNFs function was also described in other tumors of epithelial origin. We suppose that tissue-specific factors that underlie the key steps in differentiation programs of certain tissues and are able to receive or modulate signals from the cell environment might be considered as promising candidates for the role of tumor suppressors in the tissue types where they normally play the most significant role.

Activin A and activin receptors in the human thyroid: a link to the female predominance of goiter?

Activin A belongs to the TGF-beta family of growth factors involved in control of tissue formation by growth inhibition and to a family of hormones involved in human reproduction. Serum levels of dimeric activin A display a sexual dimorphism with significantly higher circulating hormone concentrations in men than in women after menopause. Since goiter is far more frequent in women than in men, we investigated the role of this sex-related growth factor in the human thyroid. Primary cultures were obtained from 3 patients with goiter, and 4 with recurrent goiter. Activin A significantly inhibited the proliferation of human thyroid follicular epithelial cells in vitro in concentrations between 0.5 and 50 ng/ml and was almost as potent as TGFbeta-1. Analysis in native tissues from 12 normal thyroids, 16 goiters, and 5 Graves thyroids demonstrated mRNA expression of the activin subunit betaA, TGFbeta-receptor type I and II, activin receptors type I receptors alk2 and alk4, and activin type II receptors actRII and actRIIb. Isoform analysis of the major functional type I activin receptor alk4 revealed the full-length transcript SKR2-1 and transcripts for the partially truncated proteins SKR2-2 and SKR2-3 in normal thyroids and goiters. Semi-quantitative RT-PCR revealed a significant 2.5-fold decrease of mRNA for alk4-1 type I activin receptors in goiter as compared to normal thyroid (p < 0.05), whereas expression of the type II receptor actRII was unchanged. These data identify a novel growth inhibitory pathway by activin in the human thyroid. Down-regulation of activin receptor type lb in goiter hints towards end-organ changes which could contribute to deficient growth inhibition. These data provide a mechanistic model how the sexually dimorphic hormone activin A may protect males from goitrogenesis.

Plant functional types and ecological strategies in Patagonian forbs

Abstract. We identified four major functional types of forbs in the Patagonian steppe, taking into account phenological and morphological traits: (1) shallow‐rooted mesophytic species (annuals), (2) shallow‐rooted non‐mesophytic species, (3) deep‐rooted evergreen species, and (4) deep‐rooted deciduous species. The major attributes differentiating these groups were the date at which seasonal growth ended, rooting depth, sprouting depth, distance between shoots of the same plant, and degree of ‘mesophytism’. We used Cluster and Principal Components Analyses to identify the groups, and the attributes determining them. Late‐growth‐cycle types had deep roots and/or high ‘xerophytism’. Late‐cycle‐xerophytic types had a great sprouting depth, and late‐cycle‐deep‐rooted types had a great distance between shoots of the same plant.On the basis of current knowledge of the structure and functioning of the Patagonian steppe, we suggested three explanations to account for these correlations. 1. Late‐cycle forbs survive summer water deficit if they have xerophytic characteristics that reduce transpiration water losses, and/or they have deep roots that increase water uptake. 2. Sprouting depth results from the shift of active buds to dormant buds at the end of the cycle. Summer forbs have a great sprouting depth because only buds which are located deep in the soil survive hot and dry summers. 3. Distant shoots of summer forbs allow them simultaneously to use the high protection against desiccating winds provided by shrubs, and the ample water availability of bare soil patches. All the functional types of forbs depend on winter water recharge to begin their cycles, but each one completes its cycle by using a different portion of the water resources available in spring and summer.

Alzheimer beta A4-amyloid protein precursor in immunocompetent cells.

The mechanism of proteolytic breakdown of the beta A4-amyloid protein precursor (APP) has attracted much attention because of its relevance for Alzheimer's disease. Apart from the pathological role of APP in the amyloidogenesis, many efforts have been made to identify the functional significance of this widely expressed protein in various biological processes. Employing biochemical techniques, we demonstrate that APP is involved in the initiation of the immune response. Upon stimulation, it is expressed by the major functional types of T-lymphocytes, i.e. CD4+ and CD8+ cells. As was demonstrated for the CD4+ lymphoid cell line H9, APP is predominantly secreted. The remaining COOH-terminal fragments generated upon secretion were highly unstable. Of the APP produced by immunocompetent cells, considerable amounts were shown to be leukocyte-derived APP (L-APP). In addition, we were able to identify the KPI-containing L-APP isoform, L-APP733, as the major expressed L-APP isoform in immunocompetent cells, including rat microglial cells and astrocytes. The L-APP expression pattern of these cells showed high similarity. These findings seem to be indicative of an important function of APP within the immune system. Therefore, APP may be involved in various immunopathogenic conditions of the periphery and in the central nervous system.

Attachments of human intrafusal fibers

The human intrafusal fibers have two major types of attachments: (1) extracapsular, involving the bag and long chain fibers which tapered into the extrafusal endomysium; and (2) intracapsular, involving only the short chain fibers which attached to the outer or inner capsule as well as to the bag, and other chain fibers. At all the attachment sites except the interfiber attachments, the intrafusal fibers showed alterations in the basement and plasma membrane, streaming of the Z band, and rod bodies. This profile was similar to the myotendinous junctions. The terminal sarcomere segment consisted of the actin filaments, thickening of the plasma membrane, and folded basal lamina. The interfiber attachments were of two types—the gap and tight junctions. There were thus two major functional types of attachment, the myotendinous type contacts which were mechanical and the interfiber attachments which represent electrical continuity between the two chain fibers.

Electrophysiology of taste-mediated functions in parabrachial nuclei of behaving rabbit

A single-unit analysis of parabrachial (PBN) neuronal activity associated with orolingual response to auditory-cued intraoral injections of basic type tastants and water revealed 7 major functional types of neurons. Several types dealt with mechanoreceptive orosensory input from superficial and/or deep receptors and from proprioceptors (possibly joint receptors). Some were multimodal in sensitivity. In one type, thermal or gustatory input acted to inhibit movement-related excitation in activity. Three types of taste-sensitive elements were distinguished. “Movement-taste sensitive” elements showed relations to orolingual movement and hedonic properties of fluid input. These cells may contribute to motivational control of licking activity. A tentative distinction was drawn between “tastehedonic” and “taste” elements. One type responded to water and showed a bias toward hedonic properties of tastants. The other type exhibited no response to water and smaller responses to tastants that had no hedonic relationship. Both, however, had common properties, including inhibitory modulation of activity in apparent anticipation of fluid delivery. In addition to serving as a gustatory relay, PBN act to integrate orolingual response to taste and other orosensory input, and may operate as an output mechanism in the ventral forebrain control of ingestive behavior.

The Secular Trend in Income Distribution by Type, 1869-1948: A Preliminary Estimate

THE present paper is an initial attempt to determine the secular trend in the proportions of each of the major functional types of to the national in the United States during as long a period of time as available data permit. It relies on the classical studies in this field, supplemented by important new data. The well known studies of King1 and Martin 2 covering the early periods were concerned with the distribution of what has come to be called income payments to individuals or personal income. The lack of adequate estimates of business savings, estimates which exclude capital gains and losses, has limited severely the use of these studies for the purpose at hand. This deficiency is now being overcome by the efforts of such researchers as Simon Kuznets 3 and Raymond Goldsmith.4 For the period since Ii9, the studies of Kuznets and the U.S. Department of Commerce Office of Business Economics (hereinafter abbreviated as O.B.E.) are well known.5 point has been reached where it may be worthwhile to combine the data of some of these studies in an effort to cast new light on the secular changes in shares during the past eighty years, recognizing from the outset that the reliability of the data diminishes progressively as the inquiry delves backward in time, that the effort to combine independent statistical studies must ride roughshod over numerous discrepancies in concepts and methods which cannot be eliminated without reworking the data to an extent impossible here, and that the well known differences between the statistical and theoretical categories in the field of distribution seriously limit the usefulness of the empirical findings in answering the important problems raised by distribution theory. The ultimate objective motivating the present investigation is to seek new light on the market power or bargaining power of quasifunctional classes of income-recipients, although the conceptual problems raised by this approach are too complex to be given more than an occasional mention in the present article. The method of procedure followed was to begin with each of the more or less comprehensive and self-consistent sets of time series, each covering a period of about twenty years and overlapping with another set at ten-year intervals, to introduce some slight changes for comparability with the other sets, and to add business savings, thereby arriving at estimates of national more or less compatible with the estimates of the shares. Annual ratios of major shares to the composite national were then computed, and from these ratios ten-year arithmetic means were drawn. The percentage point changes in arithmetic means of annual ratios in each of the overlapping sets of series were then added together to provide an admittedly rough and preliminary estimate of the secular trend in each series. The procedure was applied first to the series covering all industries and then, in order to reduce the gap between the empirical and theoretical areas of distribution analysis, to the private nonagricultural sector. Certain modifications in the above basic data are here pubI Willford I. King, The Wealth and Income of the People of the United States (New York, I9I5); The National Income and Its Purchasing Power (National Bureau of Economic Research, New York, I930). 2Robert F. Martin, National Income in the United States 1799-1938 (New York, I939); Conference Board Studies in Enterprise and Social Progress (New York, I939). 'Simon Kuznets, National Product since 1869 (National Bureau of Economic Research, New York, I936), and Capital Requirements Study (in process of completion, same organization and publisher). 'Raymond W. Goldsmith, Saving and Capital Market Study (in process of completion, National Bureau of Economic Research, New York); especially Summary of Annual Estimates of Saving, I897 to 1949, Advisory Committee Memorandum No. 4I, same publisher, February I5, I95I, mimeographed, not for publication or quotation. Preliminary published quadrennial data may be found in same author, A Perpetual Inventory of National in Conference on Research in Income and Wealth, Studies in Income and Wealth, Vol. I4 (National Bureau of Economic Research, New York, I95I), pp. 5-73. 'Simon Kuznets, National Income and Its Composition, 2 vols. (National Bureau of Economic Research, New York, I94I); reprinted in one vol., I947. U.S. Office of Business Economics, Department of Commerce, National Income: 1951 Edition. Supplement to the Survey of Current Business (Washington, D. C., I95I).