Search results for "SSP"

Volatile components from flowers of Centaurea nicaeensis All., C. parlatoris Helder, C. solstitialis L., ssp. schouwii (DC.) Dostàl wild growing in S…

2008

The volatile constituents of the flowerheads of Centaurea nicaeensis All., C. parlatoris Helder and C. solstitialis L. ssp. schouwii (DC.) Dostal were extracted by hydrodistillation and analysed by GC and GC-MS. Altogether 113 components were identified. Fatty acids and hydrocarbons were the most abundant components in the oils. Caryophyllene and caryophyllene oxide were the main compounds of the sesquiterpene fraction. The study on the biological activity of the oils shows no significant activity.

The late Carnian Rhaetian Succession at Pizzo Mondello (Sicani Mountains).

2010

Sociālais darbs ar nepilngadīgiem jauniešiem dienas centros Rīgā

2018

Maģistra darba „Sociālais darbs ar nepilngadīgiem jauniešiem dienas centros Rīgā” mērķis ir izpētīt dienas centros veiktā sociālā darba nozīmi to apmeklējošo nepilngadīgo jauniešu dzīvesspēka attīstībā. Darbā analizēta attīstības sistēmu teorija, dzīvesspēka jēdziens, piesaistes teorija, pozitīvas jaunatnes attīstības pieeja un riska perspektīva. Empīriskajā izpētē tika izmantotas kvalitatīvas pētniecības metodes – daļēji strukturētas intervijas, neformālas intervijas un novērojumi. Pētījumā piedalījās 8 sociālā darba speciālisti un 5 bijušie dienas centra klienti. Empīriskais pētījums atklāj, ka dienas centros veiktais sociālais darbs ir orientēts uz nepilngadīgu jauniešu dzīvesspēka attīs…

Isolated glyoxylic acid-water 1:1 complexes in low temperature argon matrices

2015

Abstract The 1:1 hydrogen bonded complexes between glyoxylic acid (GA) and water are studied in low temperature argon matrices. Four different complex structures were found in deposited matrices. The lowest energy conformer (T1) of GA was found to form complex, where the water molecule was attached to the opposite side of the intramolecular hydrogen bond in the molecule (T1B). Interestingly, this complex was estimated to be +8.0 kJ mol −1 higher in energy than the most stable structure (T1A), where the water is inserted into the internal hydrogen bond, and also found in solid argon but in smaller abundance. For the second-lowest energy conformer of GA (T2), the two lowest-energy complex str…

Interaction in Spoken Word Recognition Models: Feedback Helps

2018

Human perception, cognition, and action requires fast integration of bottom-up signals with top-down knowledge and context. A key theoretical perspective in cognitive science is the interactive activation hypothesis: forward and backward flow in bidirectionally connected neural networks allows humans and other biological systems to approximate optimal integration of bottom-up and top-down information under real-world constraints. An alternative view is that online feedback is neither necessary nor helpful; purely feed forward alternatives can be constructed for any feedback system, and online feedback could not improve processing and would preclude veridical perception. In the domain of spo…

Comments on “Unobservable Selection and Coefficient Stability

2019

Abstract–: We establish a link between the approaches proposed by Oster (2019) and Pei, Pischke, and Schwandt (2019) which contribute to the development of inferential procedures for causal effects in the challenging and empirically relevant situation where the unknown data-generation process is not included in the set of models considered by the investigator. We use the general misspecification framework recently proposed by De Luca, Magnus, and Peracchi (2018) to analyze and understand the implications of the restrictions imposed by the two approaches.

On the Ambiguous Consequences of Omitting Variables

2015

This paper studies what happens when we move from a short regression to a long regression (or vice versa), when the long regression is shorter than the data-generation process. In the special case where the long regression equals the data-generation process, the least-squares estimators have smaller bias (in fact zero bias) but larger variances in the long regression than in the short regression. But if the long regression is also misspecified, the bias may not be smaller. We provide bias and mean squared error comparisons and study the dependence of the differences on the misspecification parameter.

On the ambiguous consequences of omitting variables

2015

This paper studies what happens when we move from a short regression to a long regression (or vice versa), when the long regression is shorter than the data-generation process. In the special case where the long regression equals the data-generation process, the least-squares estimators have smaller bias (in fact zero bias) but larger variances in the long regression than in the short regression. But if the long regression is also misspecified, the bias may not be smaller. We provide bias and mean squared error comparisons and study the dependence of the differences on the misspecification parameter.

Bakteriālās fermentācijas produktu lipopeptīdu noteikšanas iespējas, izmantojot hromatogrāfijas – masspektrometrijas metodi

2018

Bakteriālās fermentācijas produktu lipopeptīdu noteikšanas iespējas, izmantojot hromatogrāfijas – masspektrometrijas metodi. Bērziņa Z., zinātniskais vadītājs docente Dr.ķīm Ilva Nakurte, Bakalaura darbs, 33 lappuses, 25 attēli, 2 tabulas, 20 literatūras avoti. Latviešu valodā. Literatūras apskatā apkopota informācija par lipopeptīdiem, to galvenajām iedalījumu grupām, šo savienojumu struktūru, ķīmiskajām un fizikālajām īpašībām, izceļot tās, ko potenciāli būtu iespējams izmantot inovatīvu, ārstnieciski kosmētisko līdzekļu izstrādei. Kā arī apkopotas dažādas metodes, praktiskai lipopeptīdu izdalīšanai no baktēriju kultūrām un identificēšanai. Izmantojot AEŠH/MS metodi, pētīti 4 dažādi Bacil…

Phytochemical composition, anti-inflammatory and antitumour activities of four Teucrium essential oils from Greece

2009

Abstract The essential oils of four Teucrium species were studied and 150 components, in all, were identified. All oils were rich in sesquiterpenes (50.1–55.8%). Spathulenol and δ-cadinene were the main compounds of Teucrium brevifolium oil; caryophyllene and 4-vinyl guaiacol predominated in Teucrium flavum . Carvacrol and caryophyllene oxide predominated in Teucrium montbretii ssp. heliotropiifolium , while carvacrol and caryophyllene were the most abundant components in Teucrium polium ssp. capitatum . The oil which most effectively inhibited LPS-induced NO production in macrophage cell line RAW 264.7 was that from T. brevifolium (IC 50  = 7.1 μg/ml), followed by T. montbretii ssp. heliot…