2,017 research outputs found
Mosses of Mt. Trus Madi, Sabah, Malaysia
A species list of mosses collected in Mt. Trus Madi, Sabah, between 10 September and 10 October 1996 is presented. A total of 153 taxa were collected, of which 11 are new to Borneo and five new to Sabah
ON THE DYNAMICS OF THE ISRAELI-ARAB ARMS RACE
This paper investigates the causal relationships between the military expenditures and military burden of the four major sides of the Israeli-Arab conflict, namely, Egypt, Israel, Jordan and Syria over the period 1960-2004. We utilize both the causality test suggested by Toda and Yamamoto (1995) and the generalized forecast error variance decomposition method of Pesaran and Shin (1998). Our findings suggest weak causality that runs usually from Israel’s to Arab’s military spending. The strongest links are between Israel and Syria that are still in a state of enmity. No causality was detected between Israel’s and Jordan’s military spending.Arms race, Middle East, Israeli-Arab conflict, Causality, Generalized Forecast Error Variance Decomposition
STRUCTURAL BREAKS IN MILITARY EXPENDITURES: EVIDENCE FOR EGYPT, ISRAEL,JORDAN AND SYRIA
This paper endogenously determines the timing of structural breaks in military expenditures and military burdens for the major parties involved in the Israeli-Arab conflict, namely Egypt, Israel, Jordan, and Syria over the period 1960-2004. Utilizing a test proposed by Vogelsang (1997), we find that all these countries experienced structural breaks, though at different periods in the late 70s and during the 80s. These structural breaks mark a sharp decline in the military burden that can be attributed to the peace talks that were initiated shortly after the 1973 war. When applying the Bai and Perron (1998, 2003) multiple structural break tests we detect two structural breaks for every country. The first break occurred during the 60s and demonstrated a significant rise in the military burden prior to the 1973 war, whereas the second break occurred in the late 70s and during the 80s and was characterized by a sharp decline in the military burden following the instigation of peace negotiations.Military Expenditures, Military Burden, Middle-East, Israeli-Arab Conflict, Structural Breaks.
Trogocytosis by Entamoeba histolytica Mediates Acquisition and Display of Human Cell Membrane Proteins and Evasion of Lysis by Human Serum.
We previously showed that Entamoeba histolytica kills human cells through a mechanism that we termed trogocytosis ("trogo-" means "nibble"), due to its resemblance to trogocytosis in other organisms. In microbial eukaryotes like E. histolytica, trogocytosis is used to kill host cells. In multicellular eukaryotes, trogocytosis is used for cell killing and cell-cell communication in a variety of contexts. Thus, nibbling is an emerging theme in cell-cell interactions both within and between species. When trogocytosis occurs between mammalian immune cells, cell membrane proteins from the nibbled cell are acquired and displayed by the recipient cell. In this study, we tested the hypothesis that through trogocytosis, amoebae acquire and display human cell membrane proteins. We demonstrate that E. histolytica acquires and displays human cell membrane proteins through trogocytosis and that this leads to protection from lysis by human serum. Protection from human serum occurs only after amoebae have undergone trogocytosis of live cells but not phagocytosis of dead cells. Likewise, mutant amoebae defective in phagocytosis, but unaltered in their capacity to perform trogocytosis, are protected from human serum. Our studies are the first to reveal that amoebae can display human cell membrane proteins and suggest that the acquisition and display of membrane proteins is a general feature of trogocytosis. These studies have major implications for interactions between E. histolytica and the immune system and also reveal a novel strategy for immune evasion by a pathogen. Since other microbial eukaryotes use trogocytosis for cell killing, our findings may apply to the pathogenesis of other infections.IMPORTANCE Entamoeba histolytica causes amoebiasis, a potentially fatal diarrheal disease. Abscesses in organs such as the liver can occur when amoebae are able to breach the intestinal wall and travel through the bloodstream to other areas of the body. Therefore, understanding how E. histolytica evades immune detection is of great interest. Here, we demonstrate for the first time that E. histolytica acquires and displays human cell membrane proteins by taking "bites" of human cell material in a process named trogocytosis ("trogo-" means "nibble"), and that this allows amoebae to survive in human serum. Display of acquired proteins through trogocytosis has been previously characterized only in mammalian immune cells. Our study suggests that this is a more general feature of trogocytosis not restricted to immune cells and broadens our knowledge of eukaryotic biology. These findings also reveal a novel strategy for immune evasion by a pathogen and may apply to the pathogenesis of other infections
THE IMPACT OF GATT ON INTERNATIONAL TRADE: EVIDENCE FROM STRUCTURAL BREAK ANALYSIS
In this study we test for structural changes in international trade patterns of 77 countries over the post-WWII period, to examine if they experienced a substantial increase in their trade ratios following major GATT rounds such as the Kennedy Round, or after joining GATT. Our results show that trade ratios of most of these countries exhibited structural breaks in their time paths, however, most of the postbreak paths were below the extrapolated prebreak paths. Furthermore, while the significant break years coincided closely with major regional and international events such as the oil shocks of the 70s and the East-Asian financial crisis in 1997, they occurred far before or after the time of a country's accession to GATT or the time of the major GATT rounds.International Trade, Trade Liberalization, Structural Change, Oil Shocks, Kennedy Round, East Asia, Financial Crisis.
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