SOME EFFECTS OF INCREASING SOIL SALINITY ON PLANT COMMUNITIES

1958 ◽  
Vol 36 (1) ◽  
pp. 79-89 ◽  
Author(s):  
Lloyd B. Keith
Keyword(s):  
Saline Soils ◽  
Upward Movement ◽  
Soluble Salts ◽  
Clear Cut ◽  
The Third ◽  
Natural Lake ◽  
Per Se ◽  
Prairie Community ◽  
Halophytic Communities ◽  
Prairie Vegetation

Analyses of halophytic vegetation and saline soils adjacent to three different-aged impoundments were conducted on a study area in southeastern Alberta. Two impoundments had been constructed by Ducks Unlimited (Canada), and were 4 and 8 years old. The third was a small natural lake. Mesic prairie vegetation and soils were also sampled to secure comparative data. The establishment of artificial impoundments has raised the water table, permitting a rapid upward movement of soluble salts into the surface soils from lower levels in the glacial drift. Four distinct halophytic communities were recognized: a Hordeum community around all three impoundments, a Distichlis community around the older two, and Suaeda–Chenopodium and Salicornia communities around the oldest (the natural lake). It is believed that as salt concentrations increase the mesic prairie community is replaced by a Hordeum community which in turn is replaced by a Distichlis community. Evidence of Suaeda–Chenopodium and Salicornia communities supplanting the Distichlis community is not clear cut and edaphic factors other than salinity per se are involved.

The Definition, Diagnosis, and Management of Growth-Discordant Twins: An International Census Survey

1991 ◽  
Vol 40 (3-4) ◽  
pp. 345-351 ◽  
Author(s):  
I. Blickstein
Keyword(s):  
Stress Testing ◽  
Expectant Management ◽  
Doppler Velocimetry ◽  
Diagnosis And Management ◽  
Clear Cut ◽  
Biophysical Profile ◽  
Per Se ◽  
Discordant Twins ◽  
Discordant Twin

AbstractIn order to establish a protocol considering the definition, diagnosis, and management of growth-discordant twin gestations, a questionnaire was sent to 96 authors of twin-related obstetric articles. The views of the 61 responders comprise this international census survey. The data suggest that a clear cut-off value for discordancy is still needed; however, the data indirectly supported a two-grade definition, namely, mild (> 15% and < 25% birth-weight disparity) and severe (> 25%) growth discordants. Expectant management was advocated by the majority of participants with out-patient follow-up for mild discordants, while severe discordants may preferably be hospitalized. Follow-up should be done by non-stress testing (daily - 2/wk), biophysical profile (1-2/wk), Doppler velocimetry (1/wk - bi-weekly) and sonographic biometry (bi-weekly). The opinions considering termination of pregnancy because of intertwin growth discordancy were divided; however, discordancy per se, was not considered an indication for cesarean delivery. An adapted management flowchart that summarizes the survey's data is presented and may be used as a standard for future investigations.

Discussion

1997 ◽  
Author(s):  
Roger Ling ◽  
Paul Arthur ◽  
Georgia Clarke ◽  
Estelle Lazer ◽  
Lesley A. Ling ◽  
...  
Keyword(s):  
Present Writer ◽  
Fine Tuning ◽  
Archaeological Record ◽  
Process Of Change ◽  
Clear Cut ◽  
The Third ◽  
General Terms ◽  
Modern Britain

Before looking in more general terms at the pattern of development in the insula, we may make a number of preliminary points. First of all, it bears repeating that the process of change which we have outlined was continuous, and that by classifying it in phases we have inevitably simplified the picture. Just because a particular intervention can be assigned to a time when, say, walls were being painted in the Third Style, we should not think of it as a unique, compartmentalized phenomenon; the insula was constantly evolving, and it would have continued to evolve had the eruption of AD 79 not put a stop to the process. Our phases are merely a convenient way of trying to impose some kind of chronological pattern on the chain of events. In all probability changes took place more frequently and in a more piecemeal fashion than is normally realized. It is, of course, difficult to be precise about this, because our methods of dating are too unsophisticated for the necessary fine tuning; but we may suspect that, for every major rebuilding programme, there were many minor adjustments and modifications which have left no trace, or virtually no trace, in the archaeological record. And such adjustments may have happened within relatively brief periods. One has only to look at houses in modern Britain to appreciate the nature and the frequency of the alterations which they tend to undergo, ranging from the blocking or opening of windows to loft conversions and the addition of new wings. The house in which the present writer lives has been radically enlarged on two occasions, as well as having a doorway blocked, most of the windows replaced, and part of the roof redesigned—all within the space of thirty five years, and mostly in separate operations, in other words in what can technically be regarded as distinct phases. However much the archaeologist would like to divide a building’s history into broad and clear-cut chronological categories, the reality of the situation will probably more often than not have been far more complex.

The execution of arbitrary procedures by children with autism

2001 ◽  
Vol 13 (1) ◽  
pp. 97-110 ◽  
Author(s):  
SZILVIA BÍRÓ ◽  
JAMES RUSSELL
Keyword(s):  
Children With Autism ◽  
Executive Dysfunction ◽  
Physical World ◽  
The Third ◽  
Comparison Groups ◽  
Per Se

Executive tasks typically contain a prepotent lure. In addition, they require individuals either to (a) follow arbitrary procedures or (b) update their model of the physical world. Recent research suggests that children with autism may be challenged only by executive tasks of the former kind (containing arbitrary rules). We asked whether this continues to be true when there is no prepotent lure, comparing performance on (a) a task with arbitrariness but without prepotency with (b) a task with both features and (c) a task with neither. The participants with autism performed at a lower level than comparison groups on the first and second task but not on the third task. This outcome is consistent with the view that autism is associated with difficulties in following arbitrary procedures per se. We try to locate difficulties with acting on the basis arbitrary rules in relation to more mainstream ideas about autistic executive dysfunction.

Geophysical investigation of the Beinn an Dubhaich Granite, Skye

1996 ◽  
Vol 133 (2) ◽  
pp. 171-176 ◽  
Author(s):  
N. R. Goulty ◽  
C. E. Darton ◽  
A. E. Dent ◽  
K. R. Richardson
Keyword(s):  
Magnetic Anomalies ◽  
Significant Finding ◽  
Geophysical Investigation ◽  
Previous Suggestion ◽  
Clear Cut ◽  
The Third ◽  
Minimum Depth ◽  
Valid Evidence ◽  
Granite Outcrop ◽  
Ground Magnetic

AbstractThere has been a long-standing controversy concerning the form of the Beinn an Dubhaich Granite, which intrudes Cambro-Ordovician limestones and contains enclosures of limestone at outcrop. We have undertaken a three-part geophysical investigation with the aim of resolving some issues raised by previous workers. Our most significant finding results from the measurement of a gravity profile across Beinn an Dubhaich. It reveals a negative anomaly of more than 2 mGal over the granite outcrop. Our preferred model to fit this anomaly is a steep-sided granite stock extending down to about 1 km depth, which implies that the limestone enclosures are roof pendants. In a supplementary study, we measured magnetic profiles across dykes in some of the limestone enclosures in order to determine the depth to the contact with the underlying granite. However, in the most clear-cut cases we could only determine a minimum depth of 20 m, and were unable to constrain the maximum depth. In hindsight, we suggest that microgravity surveying would be a better method for determining the thicknesses of the limestone roof pendants. In the third part of the investigation, we measured a tight grid of magnetic profiles to the northeast of the granite outcrop to test a previous suggestion that dyke-like lobes of granite intrude pre-existing fractures in the overlying limestones. We located several large magnetic anomalies associated with outcropping doleritic dykes and concluded that these had not been correctly identified in the earlier work. Consequently, the ground magnetic profiles acquired to date provide no valid evidence to support the idea of an interfingering contact between the limestones and the underlying granite.

scholarly journals Morphometric Characteristics of the Conal Coronary Artery

2020 ◽  
Vol 8 (1) ◽  
Author(s):  
Ivan Stankovic ◽  
Milica Jesic
Keyword(s):  
Coronary Artery ◽  
Insufficient Evidence ◽  
Morphometric Characteristics ◽  
Surgical Revascularization ◽  
The Third ◽  
Per Se ◽  
The Difference ◽  
The Right ◽  
Morphometric Characterization

The right conal (conus) artery either presents as the first ventricular branch of the right coronary artery (RCA) or arises directly from the aorta, in which case, it is considered the third coronary artery (TCA). Morphometric characterization of this artery is important for interpretation of coronarography, surgical revascularization of myocardium and embryological interpretations. Eight out of 23 hearts presented the TCA (34.8%). The difference in the frequency of the TCA between the sexes was statistically insignificant (p>0.05). In all the specimens, the ostium of the TCA was to the left of and superior to the ostium of the RCA. The supernumerary (third) coronary artery formed Vieussens' arterial ring in 50% of the cases with the TCA, while the conal branch of the RCA formed the anastomosis with the conal branch at a higher frequency (63% of the cases). The ratio of external diameters of the RCA and TCA was 2.84 ±0.78, while the ratio of external diameters of the RCA and its conal branch was 2.61±0.74. The difference in the ratios was statistically insignificant (p>0.05). There were no findings indicating that the presence of the TCA could be detrimental or advantageous when compared to the classical coronary scheme (right and left coronary arteries originating from the aortic sinuses). Based solely on the TCA's morphological features, there is insufficient evidence to suggest that the presence of the TCA per se, is associated with a known clinical or disease state.

scholarly journals SI TAMEN PLURES PER SE NAVEM EXERCEANT. KILKA UWAG O ODPOWIEDZIALNOŚCI ARMATORÓW

2017 ◽  
Vol 7 (1) ◽  
pp. 23
Author(s):  
Zuzanna Służewska
Keyword(s):  
Economic Activity ◽  
Third Parties ◽  
Third Party ◽  
Proper Part ◽  
Technical Term ◽  
The Third ◽  
Joint And Several Liability ◽  
Legal Relationship ◽  
Per Se ◽  
The Third Party

Si tamen plures per se navem exerceant. Several Remarks on the Liability of ShipownersSummaryThe problem discussed in this paper regards the liability of several shipowners (exercitores) managing the same ship. In the title de exercitoria actione o f the Digest there are three texts that refer to this matter: D. 14,1,1,25; D. 14,1,4 pr. and D. 14,1,4,1. The first and the last one refer to a situation in which the shipowners appointed a captain (magister navis) as their agent and thus were held liable in solidum for contracts made by him with third parties. In these cases their joint and several liability had ground in the joint appointm ent of an agent (praepositio). The second text D. 14,1,4 pr. is not very clear and refers to shipowners that were managing the same ship per se, and in this case they could be sued pro portionibus exercitionis. Such a model of liability was justified by the reservation that they cannot be deemed as being each other’s captain (neque enim invicem sui magistri videbuntur). This text was widely discussed among romanists and gave ground to various interpretations. The main questions concerned were the following: whether shipowners dealt with the third parties personally or appointed an agent (magister navis), whether a contract was stipulated by all shipowners jointly or only one o f them, whether they were partners in a partnership or conducted their business independently. According to the most common interpretation the text refers to a situation in which the shipowners conducted their activity personally in the partnership. Having accepted the above view, to justify their liability pro portionibus exercitionis one must admit that they all acted as a party in a contract or, supposing a contract was stipulated by one of them, a partnership between shipowners was a particular kind of partnership in which a contract concluded by only one of the partners resulted in the liability of the others. N one of these interpretations seems to be convincing.First of all, one must take into consideration that the word exercitor was a technical term used to define someone conducting an economic activity through his agent (magister navis) so it was normally used in the context of the whole structure of exercitio navis that was based on the scheme exercitor — magister navis. Thus it seems more likely that exercere per se means not conducting an activity personally but rather „on one’s own account”, „independently”. Besides, the reservation neque enim invicem sui magistri videbuntur suggesting that plures exercitores conducted their activity personally is dubious since it refers to a concept of mutual praepositio, which was used by glossators and commentators to justify joint and several liability of partners and it may be possible that this reservation constituted a part of the gloss or was added to the original context later by some interpreter that did not understand Ulpian’s intention.A similar conclusion arises from the comparison of the text of D. 14,1,4 pr. with texts concerning the liability of several persons on the basis of actio institoria. From the text of D. 14,3,14 it appears that if no legal relationship that guaranteed the possibility of a recourse existed among several persons liable for the act of the agent, none o f them could be sued for the full am ount (in solidum) but they were held liable pro parte. In the case of actio institoria the fact of a joint appointm ent was probably treated as a manifestation of animus societatis that made it possible to treat the persons that had nom inated jointly the institor as partners and thus held them liable in solidum for contracts made by this agent. Hence the fact that in the text o f D. 14,1,4 pr. the shipowners did not appoint jointly their agent and were held liable pro portionibus exercitionis suggests that they were not partners but each of them managed a ship on his own account.If we adm it that plures exercitores that per se navem exerceant were the shipowners that did not conduct their business together we could indicate two situations in which they could be sued pro portionibus exercitionis. The first would be the case in which each o f the shipowners appointed his own agent on the ship and the contract with the third party was stipulated by all agents acting together. The second would be the case in which the shipowners appointed the same person as their agent but the praepositio was given by each o f them separately. in both cases each o f the shipowners could be sued with actio exercitoria only for his proper part since they could not be deemed to be partners and they could not sue each other with any action for a recourse.

scholarly journals Diversity of Soils of Southern Transbaikalia (on the Example of the Daursky Reserve)

2021 ◽  
Vol 36 ◽  
pp. 79-86
Author(s):  
E. R. Khadeeva ◽  
◽  
O. G. Lopatovskaya ◽  
L. I. Saraeva ◽  
T. E. Tkachuk ◽  
...  
Keyword(s):  
Granulometric Composition ◽  
Humus Content ◽  
Biosphere Reserve ◽  
Soil Formation ◽  
Saline Soils ◽  
Soluble Salts ◽  
Chestnut Soils ◽  
Alkaline Reaction ◽  
Lake Bottom ◽  
Modern Classification

The paper presents the study of soil cover of the steppe areas on the territory of the Daursky State Nature Biosphere Reserve in Transbaikalia (East Siberia). We determined the types of soils in the area surrounding the currently dry Barun-Torey lake according to the modern classification: Chestnut typical and saline, Saline gleyed typical and sulfide (sor) typical. Typical chestnut soils are formed on the tops of lake terraces and form complexes with saline soils. Salted chestnut soils occupy transit landforms. Saline soils are confined to low relief forms of the shoreline and the bottom of the lake, where the accumulation of readily soluble salts occurs. Typical Chestnut and saline soils are characterized by a light granulometric composition and a low humus content. Sulphide and typical gleyed saline soils have a heavier granulometric composition, a highly alkaline reaction of the soil solution, a very low humus content and a high content of readily soluble salts. The natural factors of soil formation are: slightly dissected relief; arid and cryoarid climate; groundwater level; steppe and halophytic meadow vegetation. Chestnut soils that form at the tops of lake terraces are the most common. Solonchaks occupy low relief forms of the lake shoreline and lake bottom.

scholarly journals Preliminary use of a fulvic acid, as a strategy to improve water use in saline soils

2021 ◽  
Vol 53 (1) ◽  
pp. 164-175
Author(s):  
Cristián Kremer ◽  
José Díaz ◽  
Oscar Seguel ◽  
Yasna Tapia
Keyword(s):  
Electrical Conductivity ◽  
Fulvic Acid ◽  
Water Use ◽  
Irrigation Water ◽  
Chemical Properties ◽  
Residual Effect ◽  
Saline Soils ◽  
The Third ◽  
Loam Soil ◽  
Made In

An evaluation of a fulvic acid (FA) was made in a Loam soil, by selecting the best dose to achieve salt displacement under a drip emitter. In trial 1, PVC columns were filled with a loam soil and irrigated with a KCl solution of electrical conductivity (EC) of 12.5 dS m-1. Once the soil solution EC reached the value of the KCl solution, FA doses of 0, 2.1, 5.3 and 10.5 kg ha-1 were applied. The bulk electric conductivity and soil chemical properties were evaluated after 6 irrigation cycles. In trial 2, the same soil salinized with the KCl solution was placed in 0.8 m3 containers. Two irrigations treatments were performed: a control and the best FA dose from trial 1. The displacement of the salt bulb created from irrigation with a dropper in the soil profile was characterized. In trial 1, the dose of 5.3 kg ha-1 reached the lowest EC after the third irrigation. In trial 2, the selected dose reduced EC until 3.75 dS m-1 at 0.3 m depth at the third irrigation, saving 246 L of water compared to control. Additionally, the salinity bulbs were more horizontally extended in the FA treatment. Highlights: Application of FA (5.3 kg ha -1) reduced the water use by 50% compared to leaching carried out exclusively with water. The use of Fulvic acid showed to be an alternative to consider in the recovery of saline soils under drip irrigation when irrigation water is scarce. Little or not residual effect was found after the use of Fulvic acid.

Mutational analysis of transmembrane histidines in the amiloride-sensitive Na+/H+ exchanger

1995 ◽  
Vol 269 (2) ◽  
pp. C392-C402 ◽  
Author(s):  
D. Wang ◽  
D. F. Balkovetz ◽  
D. G. Warnock
Keyword(s):  
Mutational Analysis ◽  
Site Directed Mutagenesis ◽  
Directed Mutagenesis ◽  
Transport Activity ◽  
Wild Type ◽  
Clear Cut ◽  
Inhibition Concentration ◽  
Nhe1 Activity ◽  
Per Se ◽  
Nhe Isoforms

The histidine-reactive reagent, diethyl pyrocarbonate (DEPC) inhibits the human amiloride-sensitive Na+/H+ exchanger (NHE1) in stably transfected fibroblasts. NHE1 was protected by cimetidine and amiloride from DEPC, and DEPC inhibition was reversed with hydroxylamine, suggesting a role for critical histidine groups in NHE activity. We replaced the histidines (H) in putative transmembrane domains (H35, H120, H349) with glycine (G) using site-directed mutagenesis. There was no significant change in NHE activity of the H120G; H349G; H120,349G; and H35,120,349G mutants compared with wild type. The 50% inhibition concentration values for amiloride, ethyl isopropyl amiloride (EIPA), and cimetidine of the H349G mutant were significantly increased compared with the wild-type NHE1. We also examined the DEPC effect on the transport activity of the triple histidine mutant (H35,120,349G) and found that NHE1 activity was still inhibited by DEPC with reversal by hydroxylamine and protected by amiloride and cimetidine. Kinetic analysis of DEPC inhibition indicated that two "critical" histidine residues are required for NHE transport activity. Substitutions of H349 with asparagine (N), glutamine (Q), serine (S), tyrosine (Y), valine (V), leucine (L), and phenylalanine (F) were also examined. There were no changes in NHE activity of these mutants compared with wild type. The H349G and H349L mutants became more resistant to amiloride, whereas the H349Y and H349F mutants became more sensitive to amiloride. The H349S (mimics NHE3) and H349Y (mimics NHE4) mutations had only modest effects on amiloride sensitivity. These results indicate that H349 affects the interaction of NHE1 with its inhibitors, even though substitutions at this site, per se, do not appear to explain the differences in amiloride sensitivity between different NHE isoforms. Despite clear-cut effects of the H349G mutation on the competitive interaction of NHE1 with cimetidine and EIPA, this mutation did not affect the affinity of NHE1 for its cationic substrates (Na+, Li+).

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