A gazdasági teljesítmények vállalkozási mérettől függő jellemzői Magyarországon = Changing ownership and business structures in the Hungarian economy

A mögöttünk hagyott két évtizedben – tetszik, vagy sem – a magyar gazdaság 1992. évi mélypontról történő kilábalásában, majd új növekedési pályára állásában meghatározó szerepe volt a hazai forrásokat kiegészítő külföldi befektetéseknek. Ennek természetesen ára volt: a tevékenységi struktúra (termékszerkezet) módosulása, a tulajdonosi összetétel radikális átalakulása, a külgazdasági kapcsolatok irányultságának változása, a lakosság önfoglalkoztatási célú vállalkozásainak szaporodása, a gazdaságfejlesztés irányának és ütemének cikk-cakkos mozgása, az állami szerepkör fokozatos leépülése. Írásunk célja annak áttekintése, hogy a nemzetközi tőkeáramlás tendenciáinak módosulását követően – a Magyarországra érkező külföldi tőkebefektetések jelentős csökkenéséből fakadóan – a kizárólagos és többségi hazai tulajdonú szereplők (kiemelten a hazai közép- és kisvállalkozások) milyen mértékben lehetnek alkalmasak a kieső teljesítmények pótlására, illetve a gazdasági válság lecsengését követően milyen ütemű növekedést képesek biztosítani a magyar gazdaság számára. A válaszok nagy valószínűséggel az Új Széchenyi Terv szempontjából sem közömbösek. Az írást a szerkesztőség vitairatnak szánja és szívesen ad teret a témával kapcsolatos vélemények kifejtésének. / === / The economic performance during the transition period was characterized by the alternations of fulfilled hopes and unrealized expectations. The economic restructuring and changes in market relations took place during the first decade, while new – mostly foreign – investment groups entered the new market. As a result the economy was stabilized and was put on a new growth path. But after the millennium the foreign investment based economy development strategy was no more adequate. The new engine for the growth should have been the domestic small and medium enterprise sector (SME), but despite the subsidies this sector was not strengthened enough to take this role.

Gazdasági kórkép alulnézetből I. rész (Syndrome of Hungarian Economy from Bottom-view – I. part)

A rendszerváltás utáni időszak gazdasági teljesítményei a beteljesült remények és a megvalósulatlan várakozások egymást követő hullámzásait takarják. A mögöttünk hagyott két évtized első felét a gazdasági szerkezetváltás, a piaci kapcsolatok módosulása, valamint új – többségében külföldi – befektetői csoportok megjelenése jellemezte, amelyek együttes hozadéka volt a gazdaság stabilizálódása, majd az új növekedési pályára állás. Az ezredfordulót követő évtized első felére azonban a külföldi befektetésekre alapozott gazdaságfejlesztési stratégia erejét vesztette, s a helyettesítésre szánt hazai kkv-szektor – a kiemelt támogatások és a kedvezmények ellenére – nem tudott a növekedés motorjává válni. Szerzőnk – a BCE tudományos kutatója és az APEH korábbi elnöke – a versenyszektor 2000–2008. évi pénzügyi beszámolói alapján a hazai vállalkozások demográfiai, teljesítményi és eredményességi jellemzőit vizsgálja, s két részből álló tanulmányában arra keresi a választ, hogy a várakozásoktól elmaradó működési eredményekben milyen szerepe lehet a gazdaságfejlesztési stratégia hiányának, a vállalkozási teljesítmények elégtelenségének, a tőkehiánynak, illetve a pénzügyi rendszer torzulásainak. Szerkesztőségünk a tanulmányt olyan vitaindítónak tekinti, ami széles érdeklődésre tarthat számot, s szívesen vállalkozunk arra, hogy közreadunk minden jobbító szándékú gondolatot. _______ The economic performance during the transition period was characterized by the alternations of fulfilled hopes and unrealized expectations. The economic restructuring and changes in market relations took place during the first decade, while new – mostly foreign – investment groups entered on the new market. As a result the economy was stabilized and was put to a new growth path. But after the millennium the foreign investment based economy development strategy was no more adequate. The new engine for the growth should have been the domestic small and medium enterprise sector (SME), but despite the subsidies this sector was not strengthened to take this role. The author – the researcher of BCE, and the ex-president of APEH – analyses the characteristics of the domestic business demography, performance and effectiveness, based on the 2000–2008 annual financial statements of the business sector. The two-part study seeks the reason for the disappointing operation results. What role take in this phenomena the absence of economic strategy, the deficiency of business performance, the lack of capital and the financial distortions of the system. Our editorial intend this study as a debate for the public, and we would publish the ideas which improves this relevant topic.

Gazdasági kórkép alulnézetből 2. rész (Syndrome of Hungarian Economy from Bottom-view - part 2.)

A magyar gazdaság új növekedési pályára állása a kilencvenes évek végére tehető, s ebben meghatározó szerepe volt a pótlólagos erőforrásként szolgáló külföldi működőtőke-befektetéseknek. A nemzetközi tőkeáramlás ezredfordulót követő módosulása (csökkenő volumen, változó irányultság) kedvezőtlenül érintette a hazai gazdaságot, aminek egyik következménye a beruházások csökkenése és a növekedési ütem lassulása, másik következménye viszont – a jövedelemkiáramlást semlegesítő hatás elmaradása miatt – a fizetési mérleg romlása. Ebben a helyzetben halaszthatatlanná vált az államháztartási egyensúlyromlás megállítása, illetve a gazdasági fejlődés új alapokra helyezése. A szerző elemzésében – a hazai versenyszektor eredményességi és vagyoni jellemzőinek értékelésével – azt szeretné jelezni, hogy az egyensúlytalansági állapot megszüntetése nem szorítkozhat az államháztartási rendszerre, vagyis az ország helyzetének stabilizálása, majd új növekedési pályára állás nem képzelhető el a gazdaság átfogó modernizációja nélkül. Vizsgálata a ténylegesen működő (343 ezer) hazai társas vállalkozás 2000–2008. évi pénzügyi beszámolóinak adataira épül. Álláspontja szerint a mintavétel nagysága ellensúlyozza az esetleges torzító hatásokat (lásd: helyenként előforduló kreatív beszámolók), így a vállalkozások mennyiségi gyarapodása, méret szerinti megoszlása, a gazdasági tevékenység jellege, a teljesítmények és eredmények alakulása, a vállalkozói vagyon módosulása megbízhatóan értékelhető, illetve a tapasztalatok alapján a korrekciós intézkedések igénye és azok tartalma is jól körvonalazható. Tanulmányát így ajánljuk a téma iránt érdeklődőknek, a versenyszektor szereplőinek, de leginkább a gazdaságpolitika formálóinak. _________ The economic performance during the transition period was characterized by the alternations of fulfilled hopes and unrealized expectations. The economic restructuring and changes in market relations took place during the first decade, while new – mostly foreign – investment groups entered on the new market. As a result the economy was stabilized and was put to a new growth path. But after the millennium the foreign investment based economy development strategy was no more adequate. The new engine for the growth should have been the domestic small and medium enterprise sector (SsME), but despite the subsidies this sector was not strengthened to take this role. The author – the researcher of BCE, and the ex-president of APpEH – analyses the characteristics of the domestic business demography, performance and effectiveness, based on the 2000–2008 annual financial statements of the business sector. In the author’s analysis – with assessment of the domestic business sector and financial performance characteristicst - he would like to point out that the imbalance can not be confined to the elimination of state government system, that is, the country’s situation to stabilize, and then post a new growth path is not conceivable without the modernization of the economy overall. In his view, the sample size outweighed the possible distortionary effects (see occurring in places of creative accounts), so the growth of business volume, size distribution, the nature of economic activity, the evolution of performance and results, a reliable assessment of changes in the business of property and the experience on the basis of the need for corrective action, and its contents are also well delineated. Sstudy it is recommended for those interested in the topic, the business sector actors, but most of the economic policy makers.

Understanding Ten-Eleven Translocation-2 in Hematological and Nervous Systems

I proposed the study of two distinct aspects of Ten-Eleven Translocation 2 (TET2) protein for understanding specific functions in different body systems. In Part I, I characterized the molecular mechanisms of Tet2 in the hematological system. As the second member of Ten-Eleven Translocation protein family, TET2 is frequently mutated in leukemic patients. Previous studies have shown that the TET2 mutations frequently occur in 20% myelodysplastic syndrome/myeloproliferative neoplasm (MDS/MPN), 10% T-cell lymphoma leukemia and 2% B-cell lymphoma leukemia. Genetic mouse models also display distinct phenotypes of various types of hematological malignancies. I performed 5-hydroxymethylcytosine (5hmC) chromatin immunoprecipitation sequencing (ChIP-Seq) and RNA sequencing (RNA-Seq) of hematopoietic stem/progenitor cells to determine whether the deletion of Tet2 can affect the abundance of 5hmC at myeloid, T-cell and B-cell specific gene transcription start sites, which ultimately result in various hematological malignancies. Subsequent Exome sequencing (Exome-Seq) showed that disease-specific genes are mutated in different types of tumors, which suggests that TET2 may protect the genome from being mutated. The direct interaction between TET2 and Mutator S Homolog 6 (MSH6) protein suggests TET2 is involved in DNA mismatch repair. Finally, in vivo mismatch repair studies show that the loss of Tet2 causes a mutator phenotype. Taken together, my data indicate that TET2 binds to MSH6 to protect genome integrity. In Part II, I intended to better understand the role of Tet2 in the nervous system. 5-hydroxymethylcytosine regulates epigenetic modification during neurodevelopment and aging. Thus, Tet2 may play a critical role in regulating adult neurogenesis. To examine the physiological significance of Tet2 in the nervous system, I first showed that the deletion of Tet2 reduces the 5hmC levels in neural stem cells. Mice lacking Tet2 show abnormal hippocampal neurogenesis along with 5hmC alternations at different gene promoters and corresponding gene expression downregulation. Through the luciferase reporter assay, two neural factors Neurogenic differentiation 1 (NeuroD1) and Glial fibrillary acidic protein (Gfap) were down-regulated in Tet2 knockout cells. My results suggest that Tet2 regulates neural stem/progenitor cell proliferation and differentiation in adult brain.

(Table S1) Age determination of Atlantic Ocean sediment cores

Well-dated benthic foraminifer oxygen isotopic records (d18O) from different water depths and locations within the Atlantic Ocean exhibit distinct patterns and significant differences in timing over the last deglaciation. This has two implications: on the one hand, it confirms that benthic d18O cannot be used as a global correlation tool with millennial-scale precision, but on the other hand, the combination of benthic isotopic records with independent dating provides a wealth of information on past circulation changes. Comparing new South Atlantic benthic isotopic data with published benthic isotopic records, we show that (1) circulation changes first affected benthic d18O in the 1000-2200 m range, with marked decreases in benthic d18O taking place at ~17.5 cal. kyr B.P. (ka) due to the southward propagation of brine waters generated in the Nordic Seas during Heinrich Stadial 1 (HS1) cold period; (2) the arrival of d18O-depleted deglacial meltwater took place later at deeper North Atlantic sites; (3) hydrographic changes recorded in North Atlantic cores below 3000 m during HS1 do not correspond to simple alternations between northern- and southern-sourced water but likely reflect instead the incursion of brine-generated deep water of northern as well as southern origin; and (4) South Atlantic waters at ~44°S and ~3800 m depth remained isolated from better-ventilated northern-sourced water masses until after the resumption of North Atlantic Deep Water (NADW) formation at the onset of the Bølling-Allerod, which led to the propagation of NADW into the South Atlantic.

Sediment rates and structures in Bay of Kiel, Baltic Sea

Density and diversity of bottom fauna population as dependent on sediment types and water depth is largely well known in Kiel Bay. This is in contrast to structures and processes of bioturbation, although generally it has a big influence on the benthic boundary layer and its processes, e.g., the metabolism of the bottom fauna, the mechanical properties, the age dating, and the large field of chemical processes. In the densely inhabited sands and muddy sands of the shallower waters with sediment thicknesses of some decimeters only, bioturbation is usually ubiquitous, and most of the structures left are monotonously of "biodeformational" character. At greater water depths, however, where a sedimentary column of several meters of Holocene is developed, the X-ray radiographs of numerous sediment cores show heterogeneous biogenic structures with regional and stratigraphical differentiation. They are described in terms of ichnofabrics and are interpreted on ethological knowledge of the related macrobenthos species. lmportant organisms creating specific traces include the bivalve Arctica (Cyprina) islandica and the polychaete worm Pectinaria koreni. These species are abundant in Kiel Bay and produce by their crawling-plowing mode of locomotion, a characteristic biogenic stratification, the "plow-sole structure". Other typical biogenic structures are tube traces, which are left by a number of different polychaetes occurring either singly, or as U-pairs mainly in mud sediments. Although sea urchins are rare to absent in Kiel Bay, layers of their characteristic traces Scolicia occur as witness of paleohydrographic events in channel sediments of the central bay. Plow-sole traces, polychaete-tube ichnofabric, Scolicia layers and alternations of laminated and bioturbated layers are considered as building blocks of a future "ichnostratigraphy" of Kiel Bay.

Argument structure and specific language impairment: retrospect and prospect

This article reflects a collaboration between the Universities of Groningen and Reading of which Frans Zwarts was the promoter. One of the outcomes was a close attention to the learning of various aspects of argument structure by children with specific language impairment (SLI) in Dutch and English. At that time and since, the focus on deficits in grammatical morphology in these children has left verb complementation as something of a syntactic Cinderella. Here we review the findings from our studies in the 1990s. We confirm that children with SLI in both languages have problems with verb specificity, with argument structure alternations and with resultative verb predicates. The very limited number of subsequent studies on verb syntax appear to support our findings. We conclude that this is an area which will repay further scrutiny – it is high time argument structure received an invitation to the ball.

(Table 2) Terrigenous, authigenic and biogenic composition of sediments at DSDP Hole 93-603B

Pelagic sedimentation during the Early Cretaceous at Site 603 produced alternations of laminated marly limestone and bioturbated limestone-a facies typical of the "Blake-Bahama Formation" of the western Atlantic. This limestone is a nannofossil micrite, rich in calcified radiolarians, with variable amounts of organic matter, pyritized radiolarian tests, fish debris, and micaceous silt. The laminated marly limestone layers are enriched in organic matter when compared with the intervals of bioturbated limestone. The organic carbon is predominantly terrestrial plant debris; where the organic-carbon content is in excess of 1%, there is also a significant marine-derived component. Laminations can result either from bands of alternately enriched and depleted opaque material and clay, or from bands of elongate lenses (microflasers) of micrite, which could be plastically deformed pellets or diagenetic features. The alternating intervals of laminated and bioturbated structures may have resulted from combined changes in surface productivity, in the influx of terrigenous organic matter, and in the intensity of bottom circulation, which led to episodic oxygen depletion in the bottom water and sediments. Variations in the relative proportions of laminated clay-rich and bioturbated lime-rich limestone and in the development of cycles between these structures make it possible to subdivide the Lower Cretaceous pelagic facies into several subunits which appear to be regional in extent. Bioturbated limestone is dominant in the Berriasian, laminated marly limestone in the Valanginian and Barremian-lower Aptian, and well-developed alternations between these end members in the Hauterivian. The Hauterivian to lower Aptian sediments contain abundant terrigenous clastic turbidites associated with a submarine fan complex. These changes in the general characteristics of the pelagic sediment component of the Blake-Bahama Formation at Site 603 are synchronous with those in the Blake-Bahama Basin (Sites 534 and 391) to the south. Carbonate sedimentation ended in the early Aptian, probably because of a regional shoaling of the carbonate compensation depth.

Lake Tiefer See varve microfacies, bulk geochemistry, µ-XRF, vegetation openness and Cladocera record

The Holocene sediment record of Lake Tiefer See exhibits striking alternations between well-varved and non-varved intervals. Here we present a high resolution multi-proxy record for the past ~6000 years and discuss possible causes for the observed sediment variability. This approach comprises of microfacies, geochemical and microfossil analyses as well as of a multiple dating concept including varve counting, tephrochronology and radiocarbon dating. Four periods of predominantly well-varved sediment were identified at 6000-3950 cal. a BP, 3100-2850 cal. a BP, 2100-750 cal. a BP and AD 1924-present. Except of sub-recent varve formation, these periods are considered to reflect reduced lake circulation and consequently, stronger anoxic bottom water conditions. In contrast, intercalated intervals of poor varve preservation or even extensively mixed non-varved sediments indicate strengthened lake circulation. Sub-recent varve formation since AD 1924 is, in addition to natural forcing, influenced by enhanced lake productivity due to modern anthropogenic eutrophication. The general increase in periods of intensified lake circulation in Lake Tiefer See since ~4000 cal. a BP presumably is caused by gradual changes in Northern Hemisphere orbital forcing, leading to cooler and windier conditions in Central Europe. Superimposed decadal to centennial scale variability of the lake circulation regime likely is the result of additional human-induced changes of the catchment vegetation. The coincidence of major non-varved periods at Lake Tiefer See and intervals of bioturbated sediments in the Baltic Sea implies a broader regional significance of our findings.

Mineralogical (bulk rock and clay fraction) and stable isotope composition (d13C, d18O) of Aptian deposits of the Bir Oum Ali succession, central Tunisia

Alternations between siliciclastic, carbonate and evaporitic sedimentary systems, as recorded in the Aptian mixed succession of southern Tunisia, reflect profound palaeoceanographic and palaeoclimatic changes in this area of the southern Tethyan margin. The evolution from Urgonian-type carbonates (Berrani Formation, lower Aptian) at the base of the series, to intervals dominated by gypsum or detrital deposits in the remainder of the Aptian is thought to result from the interplay between climate change and tectonic activity that affected North Africa. Based on the evolution of clay mineral assemblages, the early Aptian is interpreted as having been dominated by slightly humid conditions, since smectitic minerals are observed. Near the early to late Aptian boundary, the onset of a gypsiferous sedimentation is associated with the appearance of palygorskite and sepiolite, which supports the installation of arid conditions in this area of the southern Tethyan margin. The evaporitic sedimentation may have also been promoted by the peculiar tectonic setting of the Bir Oum Ali area during the Aptian, where local subsidence may have been tectonically enhanced linked to the opening of northern and central Atlantic. Stress associated with the west and central African rift systems may have triggered the development of NW-SE, hemi-graben structures. Uplifted areas may have constituted potential new sources for clastic material that has been subsequently deposited during the late Aptian. Chemostratigraphic (d13C) correlation of the Bir Oum Ali succession with other peri-Tethyan regions complements biostratigraphic findings, and indicates that a potential expression of the Oceanic Anoxic Event (OAE) 1a may be preserved in this area of Tunisia. Although the characteristic negative spike at the base of this event is not recognized in the present study, a subsequent, large positive excursion with d13C values is of similar amplitude and absolute values to that reported from other peri-Tethyan regions, thus supporting the identification of isotopic segments C4-C7 of the OAE1a. The absence of the negative spike may be linked to either non preservation or non deposition: the OAE1a occurred in a global transgressive context, and since the Bir Oum Ali region was located in the innermost part of the southern Tethyan margin during most of the Aptian, stratigraphic hiatuses may have been longer than in other regions of the Tethys. This emphasizes the importance of integrating several stratigraphic disciplines (bio-, chemo- and sequence stratigraphy) when performing long-distance correlation.

Diatom isotope data from ODP Hole 178-1098A for the last deglaciation (12.2-12.8 ka BP)

Understanding the response of the Antarctic ice sheets during the rapid climatic change that accompanied the last deglaciation has implications for establishing the susceptibility of these regions to future 21st Century warming. A unique diatom d18O record derived from a high-resolution deglacial seasonally laminated core section off the west Antarctic Peninsula (WAP) is presented here. By extracting and analysing single species samples from individual laminae, season-specific isotope records were separately generated to show changes in glacial discharge to the coastal margin during spring and summer months. As well as documenting significant intra-annual seasonal variability during the deglaciation, with increased discharge occurring in summer relative to spring, further intra-seasonal variations are apparent between individual taxa linked to the environment that individual diatom species live in. Whilst deglacial d18O are typically lower than those for the Holocene, indicating glacial discharge to the core site peaked at this time, inter-annual and inter-seasonal alternations in excess of 3 per mil suggest significant variability in the magnitude of these inputs. These deglacial variations in glacial discharge are considerably greater than those seen in the modern day water column and would have altered both the supply of oceanic warmth to the WAP as well as regional marine/atmospheric interactions. In constraining changes in glacial discharge over the last deglaciation, the records provide a future framework for investigating links between annually resolved records of glacial dynamics and ocean/climate variability along the WAP.

Priamy a nepriamy predmet v slovenčine a španielčine

V článku sa analizujú ekvivalenty a rozdiely medzi priamym a nepriamym predmetom v španielčine a akuzatívom a datívom v slovenčine. Ďalej sa autorka snaží nájsť normy pre správne používanie zámen v datíve a akuzatíve v obidvoch jazykoch a sústredí sa na tretie osoby singuláru aj plurálu. Nakoniec sa vyvodia chyby a interferencie v používaní týchto zámen u slovensky hovoriacich.

Notas sobre la lengua guaymí en Costa Rica

Como aproximación panorámica al estudio actual del guaymí, una de las lenguas de la familia chibcha, es un análisis introductorio de los rasgos gramaticales y tipológicos generales de esa lengua. Previa información de índole antropológica e histórico-cultural, se exponen en forma analítica aspectos sintácticos, sobre la frase verbal, el morfema de negación, el de reflexivización, los sujetos dativos, los objetos directos. Señala algunas tareas pendientes, que suponen un estudio más pormenorizado y extendido.Providing a panoramic view of the present studies of the Guaymí language, one of the Chibchan languages, this is an introductory analysis of the general grammatical and typological features of that language. First, information is given on anthropological, historical and cultural aspects. Then syntactic features are described for the verb phrase, the morpheme for negation, reflexive forms, dative subjects and direct objects. Mention is made of pending tasks requiring a broader and more detailed study.

Double Hybrid Functionals and the Π-System Bond Length Alternation Challenge: Rivaling Accuracy of Post-HF Methods

Predicting accurate bond length alternations (BLAs) in long conjugated oligomers has been a significant challenge for electronic-structure methods for many decades, made particularly important by the close relationships between BLA and the rich optoelectronic properties of π-delocalized systems. Here, we test the accuracy of recently developed, and increasingly popular, double hybrid (DH) functionals, positioned at the top of Jacobs Ladder of DFT methods of increasing sophistication, computational cost, and accuracy, due to incorporation of MP2 correlation energy. Our test systems comprise oligomeric series of polyacetylene, polymethineimine, and polysilaacetylene up to six units long. MP2 calculations reveal a pronounced shift in BLAs between the 6-31G(d) basis set used in many studies of BLA to date and the larger cc-pVTZ basis set, but only modest shifts between cc-pVTZ and aug-cc-pVQZ results. We hence perform new reference CCSD(T)/cc-pVTZ calculations for all three series of oligomers against which we assess the performance of several families of DH functionals based on BLYP, PBE, and TPSS, along with lower-rung relatives including global- and range-separated hybrids. Our results show that DH functionals systematically improve the accuracy of BLAs relative to single hybrid functionals. xDH-PBE0 (N4 scaling using SOS-MP2) emerges as a DH functional rivaling the BLA accuracy of SCS-MP2 (N5 scaling), which was found to offer the best compromise between computational cost and accuracy the last time the BLA accuracy of DFT- and wave function-based methods was systematically investigated. Interestingly, xDH-PBE0 (XYG3), which differs to other DHs in that its MP2 term uses PBE0 (B3LYP) orbitals that are not self-consistent with the DH functional, is an outlier of trends of decreasing average BLA errors with increasing fractions of MP2 correlation and HF exchange.

Understanding ten-eleven translocation-2 in hematological and nervous systems

I proposed the study of two distinct aspects of Ten-Eleven Translocation 2 (TET2) protein for understanding specific functions in different body systems. ^ In Part I, I characterized the molecular mechanisms of Tet2 in the hematological system. As the second member of Ten-Eleven Translocation protein family, TET2 is frequently mutated in leukemic patients. Previous studies have shown that the TET2 mutations frequently occur in 20% myelodysplastic syndrome/myeloproliferative neoplasm (MDS/MPN), 10% T-cell lymphoma leukemia and 2% B-cell lymphoma leukemia. Genetic mouse models also display distinct phenotypes of various types of hematological malignancies. I performed 5-hydroxymethylcytosine (5hmC) chromatin immunoprecipitation sequencing (ChIP-Seq) and RNA sequencing (RNA-Seq) of hematopoietic stem/progenitor cells to determine whether the deletion of Tet2 can affect the abundance of 5hmC at myeloid, T-cell and B-cell specific gene transcription start sites, which ultimately result in various hematological malignancies. Subsequent Exome sequencing (Exome-Seq) showed that disease-specific genes are mutated in different types of tumors, which suggests that TET2 may protect the genome from being mutated. The direct interaction between TET2 and Mutator S Homolog 6 (MSH6) protein suggests TET2 is involved in DNA mismatch repair. Finally, in vivo mismatch repair studies show that the loss of Tet2 causes a mutator phenotype. Taken together, my data indicate that TET2 binds to MSH6 to protect genome integrity. ^ In Part II, I intended to better understand the role of Tet2 in the nervous system. 5-hydroxymethylcytosine regulates epigenetic modification during neurodevelopment and aging. Thus, Tet2 may play a critical role in regulating adult neurogenesis. To examine the physiological significance of Tet2 in the nervous system, I first showed that the deletion of Tet2 reduces the 5hmC levels in neural stem cells. Mice lacking Tet2 show abnormal hippocampal neurogenesis along with 5hmC alternations at different gene promoters and corresponding gene expression downregulation. Through the luciferase reporter assay, two neural factors Neurogenic differentiation 1 (NeuroD1) and Glial fibrillary acidic protein (Gfap) were down-regulated in Tet2 knockout cells. My results suggest that Tet2 regulates neural stem/progenitor cell proliferation and differentiation in adult brain.^