Mean Number Of Grains Research Articles

The effect of cultivation technologies on weed infestation and productivity of peas

The current paper has presented the study results obtained in 2020–2023, in the stationary field trial of the FSBSI “KurskFARC”. The purpose of the study was to identify and evaluate the impact of technologies with different levels of soil tillage minimization on weed infestation, the formation of yield structure elements and pea productivity in the conditions of the CBR. There have been studied four pea cultivation technologies, such as traditional (plowing at 20–22 cm, main application of N15P40K40 + top dressing with N34); differentiated (chiseling by 20–22 cm + disking by 8–10 cm, main application N15P40K40 + top dressing with N34); minimal (discing up to 8 cm, main application N15P40K40 + top dressing with N34); direct sowing (no-tillage, main application N5P14K14 + pre-sowing N10P26K26 + top dressing with N34). There has been established the advantage of traditional technology in reducing weed infestation, and direct sowing in the formation of yield structure elements, indicators of grain quality and pea productivity. The traditional pea cultivation technology reduced the total number of weeds by 1.9–2.0 times and their dry weight by 1.2–1.8 times during the period critical for the growth and development of the crop, and by 2.1–2.5 and 1.3–2.0 times before harvesting. The highest indicators of plant density for harvesting, the mean number of grains per plant and unit area, and protein percentage in grain were identified with direct sowing, which made it possible to obtain the maximum pea productivity (2.31 t/ha) and protein yield with the harvest (460.6 kg/ha). The use of traditional, differentiated, and minimal technologies contributed to a reduction of plant density before harvesting by 5.4–9.3 %, the mean number of grains per 1 m2 by 4.2–22.6 % and per plant by 0.6–18. 6 %, protein percentage in grain by 0.25–0.90 %, which led to a productivity decrease by 4.3–10.8 %, protein yield per hectare by 5.3–12.6 %.

Efficacy of Plant Derivatives in Protecting Mungbean Grains against Cowpea Weevil (Callosobruchus maculatus) under Storage Conditions in Southern Bhutan

Food grains infestation by insect pests in stores is a severe challenge in food production around the globe, especially in wet and humid regions. In Bhutan, mung bean is commonly grown for consumption as a superior source of protein. However, severe cowpea weevil infestation is observed while in storage condition. Controlling with synthetic pesticides is associated with health risks due to toxic residues which intervene in safe and healthy protection methods. Protecting the grains in-store through organic approach is imperative for consumption and seed purposes. Some botanical plant extracts are known for their protective properties which need location-specific studies based on availability and suitability. Therefore, this study was conducted to evaluate the efficacy of eight treatments (Acorus calamus rhizome powder, mustard oil, garlic cloves, turmeric rhizome powder, wood ash, Vitex negundo leaf powder, super grain bag including untreated control) against cowpea weevil (Callosobruchus maculatus) in mungbean under storage condition. The experiment was laid in a randomized complete block design with three replications. The result revealed that the lowest mean number of grains perforated and percent grain perforated were recorded in grains treated with Acorus calamus rhizome powder (0.46 & 0.20 %) followed by mustard oil (1.05 & 0.47 %) and grains stored in super grain bag (5.74 & 2.49%), which were significantly lower (P<0.001) as compared to other treatments. The lowest number of adult cowpea weevils was also recorded in grains treated with Acorus calamus and mustard oil followed by grains stored in super grain bag. Germination percentage was found highest in wood ash followed by mustard oil, Acorus calamus and garlic-treated grains while the lowest was in super grain bag. Therefore, Acorus calamus rhizome powder and mustard oil were found to be effective in managing cowpea weevil without affecting seed germination and vigour.

Selection of high-performance black-eyed cowpea (Vigna unguiculata) through GYT biplot analysis: a new methodology based on multiple characteristics

Cowpea bean is a common crop quite appreciated in Brazil. However, it is known that its low yield depending on soil and climatic conditions. The aim of this research is the selection of high-performance black-eyed cowpea through GYT biplot analysis. Twelve (12) cowpea bean strains were assessed between 2016 and. The study followed a randomized complete block design, with four repetitions; two commercial cultivars were used ascheck. The following variables were assessed: number of days required for flowering, final stand, value for cultivation, pod yield, pod length, mean number of grains per pod and grain weight. The analysis of variance showed genetic variability between strains, differences between the assessed years and different strain-performance in each growing year. Based on the GYT biplot graph, cultivar BRS Itaim, and strains L9 and L7 recorded the best performance for the set of yield characteristics. Variable ‘pod length’ had positive correlation to bedding, number of days required for flowering and number of grains per pod. Variable ‘100-grain weight’ had positive correlation to final stand, pod yield and mean grain weight per pod. Strains L9, L7 and cultivar BRS Itaim recorded the best yield regarding the assessed variables

Infestation and Damage Caused by Wheat Stem Sawflies (Hymenoptera: Cephidae) to Some Wheat Cultivars in Southeast Anatolia Region, Turkey

The European wheat stem sawfly, Cephus pygmeus (Linnaeus, 1767) and the black grain stem sawfly, Trachelus tabidus (Fabricius, 1775) are important and common pests in wheat growing areas of Turkey. These sawfly species continue to be a threat to wheat production in the southeast Anatolia Region of the country. This study was conducted to determine larval infestation rates and yield losses caused by these sawfly species in common wheat cultivars grown in the southeast Anatolia Region. Durum and bread wheat fields were surveyed to record larval infestation and damage caused by these sawfly species in four provinces (Adiyaman, Diyarbakir, Mardin and Sanliurfa) of the region. A total 100 wheat fields were randomly selected and stem samples were taken from each field during the harvest period. Spike length, mean number of grains, grain weight and 1000-grain weight were recorded from 100 infested and healthy spikes and crop losses were calculated for 16 wheat cultivars.The surveyed provinces significantly differed in infestation rates, with the highest infestation level recorded for Diyarbakir province with a mean of 17.4% (range 2.1- 54.3%), while the minimum infestation was determined in Adiyaman province with a mean of 5.3% (range 1.4-17.3%). Durum and bread wheat cultivars had negligible effects on larval infestation. Spike length of infested wheat plants was reduced by 0.9-14.4% and the mean number of grains and grain weight were reduced by 0.5-19.7% and 7.2-28.5%, respectively. The loss in 1000-grain weight was 8.9% in bread wheat cultivars, while the loss was 7.9% in durum wheat cultivars. It was concluded that the loss in 1000-grain weight reached 10.9%. Therefore, appropriate control measures should be taken against stem sawflies in high-infestation locations.

Influence of cooling rates on temperatures phase transitions and on microstructure of aluminium alloy EN AW‐5083

AbstractThe casting of different forms and dimensions of aluminium alloy EN WA‐5083 test samples and the usage of different types of mould materials resulted in achieving different cooling rates of samples. The methods used were simple thermal analysis, using casting into a measuring cell made by the Croning process and using casting into a cone‐shaped measuring cell, as well as simultaneous thermal analysis using the method of differential scanning calorimetry. Significant temperature phase transitions and times of solidification were determined, and the dependence model of the solidification time on the sample cooling rate was obtained. Determining the mean number of grains per unit area on samples after having performed the simple thermal analysis and differential scanning calorimetry makes it possible to develop a dependence model of the mean number of grains per unit area on the cooling rate. These models are the basis for carrying out numerical simulations of solidification and microstructure development in the cone‐shaped measuring cell, and the comparison of the distribution of the mean number of grains per unit area obtained by simulation with the one obtained experimentally. The obtained results represent a part of the preliminary tests of the microstructure development of industrially cast ingots of EN AW‐5083 alloy depending on the local ingot cooling rate.

Pollination and fruit set in pumpkin (Cucurbita pepo) by honey bees

Species of Cucurbitaceae are cultivated worldwide and are depend on bee pollination for fruit set. Field and lab experiments were conducted at Cornell University, Ithaca, NY, during 1996 and 1997 to determine Howden pumpkin (Cucurbita pepo L.) pollen removal and deposition by honeybees and factors relating to male flower attractiveness. Several parameters were evaluated in flowers at anthesis: (1) removal of pollen from anthers by honey bees, (2) pollen deposition on the stigma by honey bees, (3) amount of pollen on the body of honey bees, (4) fruit set after bee pollination, and (5) male flower nectary's pores and flower attractiveness. Honey bees carried between 1,050 to 3,990 pollen grains and 13,765 were removed from an anther after one visit. The amount of pollen deposited on the stigma by the honey bees varied according to the number of visits, from 53 grains with one visit, to 1,253 grains with 12 visits, and the mean number of grains in each visit varied from 53 to 230 grains. The percentage of established fruits was higher (100%) when the flowers received 12 visits of Apis mellifera, corresponding to a load 1,253 pollen grains. The attractiveness of the male flower for pollen and nectar collection was increased by the degree of opening of the access pore to the nectary in the flower.

On the origin of the stress decrease for nickel polycrystals with few grains across the thickness

The mechanical behaviour under uniaxial and loading/unloading tensile tests of high purity nickel with different number of grains across the thickness is studied experimentally. The specimens have a constant 500 μm thickness and the mean number of grains across the thickness (i.e., thickness “ t” to grain size “ d” ratio) lies between 0.9 and 15. An extended microstructural study is operated and no change of the microstructure appears with a modification of t/ d. The experimental results show that the t/ d ratio affects the hardening stages, flow stress, intragranular and intergranular backstress of the samples. For specimens with few grains across the thickness, the flow stress is reduced due to a decrease in the intragranular backstress. The main explanation of these results is a delay of the generalization of cross-slip for the lowest t/ d ratio specimens due to surface effects.

Avaliação de danos causados pelo Barley yellow dwarf virus: PAV em cultivares de trigo no Brasil

Com o objetivo de avaliar os danos causados pelo Barley yellow dwarf virus - PAV (BYDV-PAV), em cinco cultivares de trigo (BRS 177, BRS 179, BRS 194, BRS Camboatá e BRS Angico), foi conduzido um experimento no telado da Embrapa-Trigo (Passo Fundo RS) no ano de 2005. Os danos induzidos pelo BYDV-PAV foram determinados por meio de análise de características agronômicas (estatura das plantas e massa de matéria seca) e do rendimento (número de afilhos, espigas e grãos por planta; massa de mil grãos). Os dados foram submetidos à análise de variância e as médias ao teste de Tukey a 5%. Danos significativos em função da infecção viral foram observados em todas as variáveis avaliadas. A característica agronômica mais afetada foi a massa de matéria seca, que variou de 26,1% (BRS 177) a 51,4% (BRS 179). Para estatura de plantas foram observadas reduções de 12,5% (BRS 177) a 15,5% (BRS Camboatá). O rendimento total de grãos foi o mais afetado pela infecção viral, sendo que, danos significativos foram observados em todas as cultivares, cuja redução variou de 34,2% (BRS Camboatá) a 60,8% (BRS 179). No número médio de afilhos por planta, apenas as cultivares BRS Angico e BRS 179 apresentaram reduções de 20% e 26,6%, respectivamente. A redução do número médio de grãos variou de 26,1% (BRS Camboatá) a 54,3% (BRS 179). Também ocorreu diminuição no peso de mil grãos com redução que variou de 16,9% (BRS Camboatá) a 38,4% (BRS 194).

Structural Homogeneity of Direct-Chill Cast Ingots of Aluminum Alloy EN AW-5083

Structural homogeneity of direct-chill (DC) cast ingots of aluminum alloy EN AW-5083 was investigated in terms of grain size and grain distribution using the Latin square experimental design. The ingot cross-sectional homogeneity, the grain sizes, and the mean grain number per unit area were determined at precise, statistically defined locations in the slice by means of a semiautomatic method for measuring mean lineal intercept lengths. Based on the analysis of the differences in the number and distribution of grains between the slices cut from the ingot front and those from its rear, a general assessment of the ingot structural homogeneity was made. Analysis of variance showed the highly significant differences, in grain number in specimens taken from the ingot front section to be related to slice height/ingot depth and in those taken from the ingot rear section to individual charges and slice height. The grand means of the mean number of grains per unit area for the ingot front and rear sections show relatively high values with respect to ingot size. The obtained correlation coefficient, which suggests a good agreement between the number and distribution of grains at the ingot front and those at its rear, is indicative of good structural homogeneity of the ingot in general.

NGF prevents further atrophy of cholinergic cells of the nucleus basalis due to cortical infarction in adult post-hypothyroid rats but does not restore cell size compared to euthroid rats

We have tested the hypotheses that nerve growth factor treatment in adult post-hypothyroid rats can: (1) restore cross-sectional area of cholinergic cells of the nucleus basalis and (2) prevent further atrophy of these neurons following cortical infaction. In addition, we assessed the expression of p75 NGFR and p140 trkA mRNAs in the nucleus basalis cells of post-hypothyroid rats. Rats were rendered hypothyroid by the addition of propylthiouracil to their diet beginning on embryonic day 19 until the age of 1 month. At this time both the pups and their dams continued to receive 0.05% propylthiouracil in their diet and the pups were thyroidectomized. At 60 days, propylthiouracil treatment was interrupted and thyroxine levels were restored to normal by daily subcutaneous administration of physiological levels of thyroxine. Morphometric analysis identified atrophied nucleus basalis magnocellularis cholinergic cells at two ages, days 75 and 105, identified by in situ hybridization for p75 NGFR and p140 trkA mRNAs in methylene blue stained cells (day 75) and choline acetyltransferase immunostaining (day 105). The mean number of silver grains (pixels) per μm 2 (mean±S.E.M.) of cell body cross-sectional area for p75 NGFR mRNA in the nucleus basalis magnocellularis of euthyroid rats was 3.43±0.89, which was not statistically different from post-hypothyroid animals (4.02±1.07). A similar finding was noted for p140 trkA mRNA: mean number of grains in the euthyroid group was 5.54±0.96 and was not statistically different from the post-hypothyroid group (6.32±1.45). Nerve growth factor treatment in adulthood (between days 75 and 82) did not restore cross-sectional area from early thyroid deprivation. However, it prevented further atrophy of nucleus basalis magnocellularis neurons following cortical devascularization inflicted in adulthood (day 75).

Steady state analysis of hypothalamic GnRH mRNA levels in male Syrian hamsters: influences of photoperiod and androgen.

An in situ hybridization assay, utilizing a free floating technique was used to estimate the steady state levels of hypothalamic luteinizing hormone-releasing hormone (GnRH) mRNA levels in the brains of male golden hamsters maintained in different photoperiods. In situ histochemistry was performed using a 32P-labelled 66-nucleotide long oligomer complementary to the sequence of the human GnRH mRNA coding region. The oligonucleotide hybridized specifically to mRNA encoding the GnRH precursor as suggested by the distribution of labelled neurons and as shown by an RNAse protection assay on septal and preoptic-hypothalamic mRNA from gonadally regressed hamsters. To test the hypothesis that short-day photoperiods reduce GnRH synthesis, intact male hamsters or castrated males bearing subcutaneously inserted testosterone implants were exposed to long-day (14 h light:10 h dark) or short-day (10 h light 14 h dark) photoperiods for 4 weeks. Exposure to short day lengths never caused a decrease in GnRH expressing neurons and actually was associated with an increase in the number of radiolabelled cells specifically in the diagonal band of Broca/medial septum in the gonadally intact group. The mean number of grains per labelled cell for the short day animals similarly was not reduced from that seen in long day animals. The results are consistent with previous studies on photoperiod and GnRH content in the same brain regions and support the notion that the suppression of the synthesis of GnRH does not accompany the low levels of LH secretion observed during the early stages of reproductive quiescence in this species.

125I]Bolton-Hunter Neuropeptide-Y-Binding Sites on Folliculo-Stellate Cells of the Pars Intermedia ofXenopus laevis: A Combined Autoradiographic and Immunocytochemical Study*

It has previously been established that neuropeptide-Y (NPY) is a potent inhibitor of alpha MSH release from the pars intermedia of the amphibian Xenopus laevis. The location of binding sites for NPY in the pars intermedia of the pituitary has now been studied with light microscopic autoradiography, using a dispersed cell labeling method with the specific NPY receptor ligand [125I]Bolton-Hunter NPY. The majority of radioactive labeling was associated with folliculo-stellate cells; the percentage of labeling as well as the mean number of grains were approximately 5 times higher for folliculo-stellate cells than for melanotropes. An excess of nonlabeled NPY drastically reduced radiolabeling of folliculo-stellate cells, but had no effect on the degree of labeling of melanotropes. These results show that folliculo-stellate cells of X. laevis possess specific binding sites for NPY and indicate that NPY exerts its inhibitory action on the release of alpha MSH in an indirect fashion, by acting on the folliculo-stellate cells.

Regulation of Pro-Gonadotropin-Releasing Hormone Gene Expression by Sex Steroids in The Brain of Male and Female Rats

The fine modulation of gonadotropin gene expression and secretion is well recognized to be regulated by sex steroids through their direct action both at the anterior pituitary level and on the pulsatile pattern of GnRH secretion at the hypothalamic level. Since the influence of sex steroids on hypothalamic GnRH mRNA levels remains to be elucidated, quantitative in situ hybridization was used to study the effect of sex steroids on cellular levels of pro-GnRH mRNA in adult rats of both sexes. The effects of 14-day gonadectomy as well as administration of 17 beta-estradiol (E2, 0.25 micrograms) or dihydrotestosterone (DHT, 100 micrograms) twice a day during 14 days to gonadectomized animals were evaluated. In addition, the effect of progesterone (P, 2 mg, twice daily) alone or in the presence of E2 was also studied in ovariectomized animals. Hybridization was performed using a 35S-labeled cDNA probe encoding rat pro-GnRH and the corresponding mRNA levels were assessed by counting the number of silver grains overlying labeled neurons. In male rats, castration induced a highly significant 65% increase (compared to intact rats) in the mean number of grains per neuron. Administration of E2 or DHT to castrated animals completely prevented the post castration rise in pro-GnRH mRNA levels. In female animals, the effect of ovariectomy was less striking than in the male, a 25% increase (P less than 0.001) being observed. Treatment with E2 or DHT also completely prevented the increase in pro-GnRH mRNA levels induced by ovariectomy. Moreover, treatment with P in ovariectomized animals markedly potentiated the inhibitory effect of E2 on pro-GnRH mRNA levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Tyrosine hydroxylase mRNA in the neurons of the tuberoinfundibular region and zona incerta examined after gonadal steroid hormone treatment.

The dopamine-producing neurons of the tuberoinfundibular region are known targets of estrogen and progesterone, and are of considerable neuroendocrine importance. To determine the anatomical distribution, and number of cells that contain tyrosine hydroxylase (TH) mRNA in the tuberoinfundibular region and other regions of the brain we carried out in situ hybridization on sections prepared from ovariectomized female rats given either oil vehicle, or estrogen, or estrogen plus progesterone. The intensity of label per cell was assessed to compare the relative amount of mRNA found per cell among TH-mRNA containing cells. [3H]cRNA probes to the rat TH sequence were used. Autoradiograms demonstrated the presence of TH-mRNA in the cytoplasm of cells in the arcuate and periventricular nuclei, zona incerta, substantia nigra, and the adrenal medulla. The number and anatomical distribution of cells that contained TH-mRNA was identical to the number and distribution of cells previously demonstrated by others to contain TH immunoreactivity. In the arcuate and periventricular nuclei, compared to treatment with estrogen alone, estrogen plus progesterone did lead to a statistically significant decrease in the number of TH mRNA-containing cells we could detect. No alteration in the mean number of grains per cell, among cells detected as containing TH-mRNA was found in any group. In contrast, these same hormone treatments had no effect on the number TH-mRNa producing cells we could detect in the zona incerta. Most of the cells in the zona incerta are found within the same tissue sections as arcuate/periventricular cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Genetic variation, heritability and path-analysis in landraces of bread wheat from southwestern Iran

Nine pure lines of bread wheat collected from landraces of southwestern Iran and one local Iranian cultivar from the same area were used to estimate genetic variation and heritability for 12 developmental and yield component characters. Path-analysis was used to partition the genetic correlations between some of the characters into direct and indirect effects. Mean values for these lines were also compared with those of five improved cultivars from Iran and California. The goal of the experiment is to breed improved landraces and/or modern cultivars for areas of low input agriculture in southern California, southwestern Iran, and regions with similar environmental and agronomic conditions. Moderate genetic variation was displayed by the number of effective heads per plant, number of grains per head, and grain weight in the landrace genotypes. The heritability estimates ranged from 43 to 97%. Expected genetic advance with selection of the highest 5%, expressed as percent of the mean, was around 20% for number of heads per plant, number of grains per head, and 1000-grain weight. Days to booting, to heading, and to anthesis were positively correlated but none of them were significantly associated with days to maturity. Plant height had a negative genetic correlation with number of grains per head, 1000-grain weight, grain yield, and harvest index. The genetic correlation between number of heads per plant and number of grains per head, 1000-grain weight, and harvest index was also significantly negative. Harvest index had a negative genetic correlation with days to booting, to maturity, plant height, number of heads per plant, and straw yield and a positive correlation with number of grains per head, 1000-grain weight, and grain yield. Days to maturity, plant height, number of heads per plant, number of grains per head, 1000-grain weight, and harvest index each had a positive direct effect on grain yield. The first two characters exhibited the highest and lowest direct effects, respectively. The positive direct effects of days to maturity, plant height, and number of heads per plant, however, were partially or completely counter-balanced by their strong negative indirect effects through number of grains per head, 1000-grain weight, and harvest index. Pathanalysis indicated that late and tall landrace genotypes tend to produce more heads per plant, but with fewer number of grains per head, smaller grains, and lower harvest index. Comparisons between the local lines and the improved cultivars revealed that, in general, the former were much taller and produced a larger number of non-effective tillers. Mean number of grains per head, grain weight, harvest index, and grain yield of local lines were smaller than those of improved cultivars. Our observations indicate that the landraces could be improved by selecting for shorter genotypes with smaller numbers of tillers per plant, but with larger numbers of grains per head and heavier grains.

Effects of acid mist on invivo pollen tube growth in red maple

The effects of mist acidity on invivo pollen germination and tube elongation of red maple (Acerrubrum L.) were investigated. Branches with female flowers were exposed to simulated mist at pH values of 5.6, 4.6, 3.6, and 2.6. After exposure, stigmas were pollinated with fresh, untreated pollen. Following a growth period of 24 h, styles were excised, stained, and observed with fluorescence microscopy to determine the number of grains that had germinated and the number of tubes that had grown to the base of the style. Both germination and tube growth were sensitive to the pH of mist. During one trial, as mist pH decreased from 5.6 to 2.6, the mean number of grains that germinated decreased from 60 to 19 and the mean number of tubes that grew to the base of the style decreased from 3.8 to 1.0. Only at pH 2.6 was there a significant relationship between number of germinating pollen grains and number of tubes reaching the base of the style. The effects of acidity on pollen germination invivo were similar to, but not as severe as, those obtained previously with pollen germinated invitro.

In situ hybridization analysis of osmotic stimulus-induced changes in ribosomal RNA in rat supraoptic nucleus.

A quantitative in situ hybridization analysis was used to investigate changes in levels of ribosomal RNA (rRNA) in neurons of the supraoptic nucleus (SON) of rats stimulated osmotically by giving 2% NaCl as drinking solution for 0 (control rats), 1, 4, and 14 days. The quantitation was autoradiographically accomplished by in situ hybridization with a nick-translated tritiated ribosomal DNA probe and with the use of computer-based image analysis system. The mean number of grains per neuron in the ventral SON was significantly increased: 1.8-fold for 1 day, 2.9-fold for 4 days, and 1.7-fold for 14 days of salt loading, whereas the mean number of grains per neuron in the dorsal SON was increased 1.3-fold for 1 day, 2.5-fold for 4 days, and 1.7-fold for 14 days. Kolmogorov-Smirnov analysis of frequency histograms of grains per neuron indicated that the amount of rRNA in neurons in the ventral and dorsal SON was significantly increased by osmotic stimulation. These increases were accompanied by increases in cell size. The subcellular location of hybridizable rRNA in magnocellular neurons was altered by osmotic stimulation. Following 1-14 days of salt-drinking, rRNAs appeared to be more unevenly distributed throughout the cytoplasm. These findings are consistent with the notion that hyperosmotic stimulation has a substantial effect on the expression of rRNA genes in neurons of both the ventral and dorsal SON.

In situ hybridization detection of estradiol-induced changes in ribosomal RNA levels in rat brain

In this study, quantitative assessment of estradiol (E 2)-induced changes in levels of ribosomal RNA within brain regions concentrating the hormone was accomplished by in situ hybridization with nick-translated tritiated ribosomal DNA probes and use of a computer-based image analysis system. Ovariectomized rats were either implanted with estradiol capsules for 6 h, 24 h, or 15 days, or sham-implanted under the same time course to serve as controls. The mean number of grains, somal area, and grain density of neurons within three E 2-concentrating brain regions, the ventrolateral portion of the ventromedial and the arcuate nuclei of the hypothalamus (VL-VMN and ARC, respectively) and the corticomedial nucleus of the amygdala (AMY) were determined. In the VL-VMN and ARC, levels of rRNA were significantly increased after 6 h of E 2 treatment (70% and 30%, respectively) and after 24 h of E 2 treatment (60% and 62%, respectively). However, these effects on rRNA levels in VL-VMN and ARC were not observed after prolonged exposure of 15 days to the hormone. Neuronal hypertrophy was present only after 24 h of E 2 treatment in the VL-VMN and ARC (32% and 14%, respectively). No changes were found in the AMY. As an additional internal control, measurements were also collected from the dorsomedial portion of the VMN (DM-VMN), a region with few E 2-concentrating neurons. No changes in any of the parameters were found in DM-VMN at any time after exposure to the hormone. By extending the in situ hybridization technique to the quantitative level, these findings demonstrate differential estrogenic regulation of a known gene product, rRNA, in rat brain that is temporally and regionally specific.

Growth fraction of myelocytes in normal human granulopoiesis.

The labelling index (LI) of myelocytes (M) after flash labelling of normal human bone marrow cells with [3H]-thymidine ([3H]TdR) is always lower that the LI obtained for myeloblasts (MB) and for promyelocytes (PM). This fact can be interpreted in two ways: it may mean that the duration of the G1 phase of the cell cycle is longer in M than in MB or PM, or it may mean that the proportion of cells in cycle, i.e., the growth fraction (GF), is lower in the M population than in MB or PM. The evolution of the LI and of the mean number of grains per cell was monitored in [3H]TdR-labelled normal bone marrow during in vitro incubation for 50 hr. The generation time, measured by the halving time of the mean number of grains per cell after flash labelling, was similar for M to that for MB and PM. During continuous labelling, the LI of MB and PM reached 1 and the LI value for M never rose to more than 50% of the values recorded for MB and PM after 30 hr. These findings give support to the second hypothesis, i.e., a lower GF in the M population. Good correlation was found between the LI of M and the proportion of mature polymorphonuclear cells in the bone marrow of normal subjects and of patients with chronic benign neutropenia or hyperleucocytosis. Variations in the M growth fraction could be a medium-term (2-3 days) regulatory factor in granulocyte production.

The Granular Structure of Snow: An Internal-State Variable Approach

AbstractA statistical model characterizing the granular structure of snow is developed using quantitative stereology. The model is based on specific parameters (e.g. bond radius, grain-size, etc.) which take the form of internal-state variables in a constitutive theory for high-rate deformation of snow. In addition to parameters developed by other authors in previous investigations, a new parameter characterizing the mean bond length is developed. More significantly, general relations are derived for the mean number of bonds per grain and mean number of grains per unit volume without making any assumptions regarding the shape or size of the ice grains, or their respective distributions.