Aproximación a los problemas de aprendizaje de la estructura y formación del suelo en el alumnado de 12 a 17 años

In a longitudinal study, carried out with 12- 17 year old students, to know learning obstacles and their evolution through schooling years, on the scientific concept of soil, we have found important data of learning problems on these topics, showing the established inefficiency of transmission of scientific knowledge to conceptual change. Lastly, we point out some implications for the teaching and significative learning of these concepts

1,3-Dipolar cycloadditions of azomethine imines

Azomethine imines are considered 1,3-dipoles of the aza-allyl type which are transient intermediates and should be generated in situ but can also be stable and isolable compounds. They react with electron-rich and electron-poor olefins as well as with acetylenic compounds and allenoates mainly by a [3 + 2] cycloaddition but they can also take part in [3 + 3], [4 + 3], [3 + 2 + 2] and [5 + 3] with different dipolarophiles. These 1,3-dipolar cycloadditions (1,3-DC) can be performed not only under thermal or microwave conditions but also using metallo- and organocatalytic systems. In recent years enantiocatalyzed 1,3-dipolar cycloadditions have been extensively considered and applied to the synthesis of a great variety of dinitrogenated heterocycles with biological activity. Acyclic azomethine imines derived from mono and disubstituted hydrazones could be generated by prototropy under heating or by using Lewis or Brønsted acids to give, after [3 + 2] cycloadditions, pyrazolidines and pyrazolines. Cyclic azomethine imines, incorporating a C–N bond in a ring, such as isoquinolinium imides are the most widely used dipoles in normal and inverse-electron demand 1,3-DC allowing the synthesis of tetrahydro-, dihydro- and unsaturated pyrazolo[1,5-a]isoquinolines in racemic and enantioenriched forms with interesting biological activity. Pyridinium and quinolinium imides give the corresponding pyrazolopyridines and indazolo[3,2-a]isoquinolines, respectively. In the case of cyclic azomethine imines with an N–N bond incorporated into a ring, N-alkylidene-3-oxo-pyrazolidinium ylides are the most popular stable and isolated dipoles able to form dinitrogen-fused saturated and unsaturated pyrazolopyrazolones as racemic or enantiomerically enriched compounds present in many pharmaceuticals, agrochemicals and other useful chemicals.We acknowledge continued financial support from the Ministerio de Ciencia e Innovación (MICINN) (projects CTQ2007-62771/BQU, CTQ2010-20387, CONSOLIDER INGENIO 2010-CDS2007-00006, CTQ2011-24151, and CTQ2011-24165), the Ministerio de Economía y Competitividad (MINECO) (projects CTQ2013-43446-P, CTQ2014-51912-REDC, and CTQ2014-53695-P), FEDER, the Generalitat Valenciana (PROMETEO 2009/039 and PROMETEOII/2014/017), and the University of Alicante

Glycerol steam reforming with low steam/glycerol ratio in a two-zone fluidized bed reactor

The production of hydrogen from glycerol steam reforming has been studied in several reactors. In conventional reactors the catalyst is deactivated by coke: in fixed bed reactors plugging was observed if a low steam/glycerol ratio was employed, while in fluidized bed reactors it was possible to operate for a longer time-on-stream. The use of a two-zone fluidized bed reactor is studied in this work, as a method to counteract the problem of catalyst deactivation by coke. The glycerol reforming takes place in the upper part of this reactor while the catalyst is simultaneously regenerated in the lower part, where a stream of a regenerating gas is introduced. It has been found that CO2, O2 or H2O can act as regenerating gas in a two-zone-fluidized bed reactor, allowing steady state operation at a water:glycerol molar ratio as low as 1.25. The effect of the operating conditions has been studied and the yield to the main products was compared with the calculated values assuming thermodynamic equilibrium

Aplikasi Kawasan Rawan Banjir dan Rekomendasi Tempat Evakuasi Menggunakan Data DEM dan Berdasarkan Jarak Terdekat

Banjir adalah bencana alam yang sering terjadi setiap musim hujan. Bencana ini tidak hanya menyebabkan kerugian harta benda, tetapi juga korban manusia. Untuk itu dalam upaya mitigasi banjir, diperlukan pemetaan tentang daerah yang rentan dan memiliki risiko terhadap banjir. Pada saat terjadinya hujan masyarakat sulit memperkirakan kapan akan terjadi banjir dan kapan akan berhentinya banjir dan daerah mana saja yang terkena banjir jika pada saat terjadinya banjir dan masyarakat harus mengungsi kemana. Berdasarkan permasalahan tersebut maka dalam penelitian ini dibangun sebuah sistem yang memberikan informasi daerah rawan banjir dan rekomendasi tempat evakuasi menggunakan data DEM dan berdasarkan perhitungan jarak terdekat. Aplikasi ini bertujuan untuk memberikan informasi peta persebaran titik rawan banjir, informasi kapan akan terjadinya banjir dan memberikan informasi tempat evakuasi pada saat terjadinya banjir. Aplikasi ini dibangun menggunakan metode data DEM. Data DEM digunakan untuk mendapatkan data kontur ketinggian yang disimulasikan untuk menjadi data kawasan rawan banjir dengan ketinggian air 5 meter. Titik evakuasi berdasarkan jarak terdekat yang dianggap aman dari area kawasan banjir. Hasil pengujian dengan menggunakan metode blackbox menunjukan bahwa aplikasi ini dapat berjalan dengan baik dan memberikan informasi peta persebaran titik kawasan rawan banjir serta memberikan informasi terkini banjir yang sedang terjadi sehingga layak digunakan untuk memberikan informasi kawasan banjir

Destined for Destitution: Intergenerational Poverty Persistence in Indonesia

We estimate intergenerational poverty persistence in Indonesia using a panel dataset. to the best of our knowledge, this is the first such study looking at the issue in the Indonesian context. different from the majority of studies on this issue, we include controls for several household and individual characteristics, including for living arrangements. moreover, to circumvent data issues that plague earnings data in developing countries, we use chronic poverty status as a long-term parental welfare measure. we find there is a substantial intergenerational mobility away from poverty among children from poor households. however, the risk of continuing to live in poverty as adults is 35 percentage points higher for children from chronically poor households than for children from households which are not chronically poor. keywords: chronic poverty, intergenerational mobility, children, welfare, Indonesia jel classifications: i32, j6

The Effects of Parental Death and Chronic Poverty on Children\u27s Education and Health: Evidence From Indonesia

Using a sufficiently long-spanning longitudinal dataset, we estimate the short and long term effects of maternal and paternal death on children\u27s school enrollment, educational attainment, and health in Indonesia, then compare them to the effect of chronic poverty. we also investigate whether there are any gender dimensions in the effects. we find that young maternal orphans have worse educational outcomes than non-orphans, with the effect getting worse over time. however, we find no significant effect of orphanhood on health. however, chronically poor children have worse health and education outcomes. among young children, the effect of maternal orphanhood on education is significantly more adverse than that of chronic poverty. finally, chronically poor orphans do not suffer adverse effects beyond the effects of chronic poverty. keywords: orphanhood, chronic poverty, education, health, children, Indonesia jel classification: i10, i21, i3

Analisis Saluran Pemasaran Kelapa (Cocos Nucifera L)

Penelitian ini bertujuan untuk mengetahui saluran pemasaran kelapa mulai dari produsen sampai ke konsumen, besarnya marjin pemasaran pada masing-masing lembaga pemasaran kelapa dari produsen ke konsumen, dan persentase harga yang diterima petani (Farmer\u27s Share) dalam proses pendistribusian kelapa di Desa Ciakar Kecamatan Cijulang Kabupaten Pangandaran. Metode yang digunakan dalam penelitian ini adalah metode survei adalah metode penelitian yang dilakukan untuk mengadakan pemeriksaan dan pengukuran-pengukuran terhadap gejala empiris yang berlangsung di lapangan atau lokasi penelitian, umumnya dilakukan terhadap unit sampel yang dihadapi sebagairesponden dan buka seluruh populasi sasaran. Sampel yang diambil sebagai responden sebanyak 30 orang petani, sedangkan jumlah pedagang pengumpul 3 orang, pedagang pengecer 2 orang, dan pedagang besar 2 orang. Data yang dikumpulkan dianalisis secara deskriptif sedangkan untuk mengetahui marjin pemasaran, keuntungan pemasaran yang diperoleh setiap lembaga pemasaran dan persentase harga yang diterima petani (Farmer\u27s Share) menggunakan rumus Sudiyono (2004). Hasil penelitian menunjukkan bahwa :1. Terdapat dua saluran pemasaran kelapa dari Desa Ciakar ke Pasar Cirebon yaitu :Saluran 1:Petani → Pedagang Pengumpul → Pedagang Besar Pasar Cirebon → Pedagang Pengecer PasarCirebon → KonsumenSaluran II:Petani → Pedagang Pengumpul → Pedagang Pengecer Pasar Cirebon → Konsumen2. Marjin pemasaran pada masing-masing lembaga pemasaran pada saluran 1 di pedagangpengumpul Rp. 500,- per butir, di pedagang besar Rp. 200,- per butir dan di pedagang pengecer200,- per butir. Sedangkan pada saluran II besarnya marjin pemasaran di pedagang pengumpulRp. 500,- per butir, dan di pedagang pengecer Rp. 400,- per butir.3. Bagian harga yang diterima petani atau Farmer\u27s Share pada saluran 1 dan saluran II adalah sama sebesar 43,75 % karena di tingkat petani pada saluran I dan saluran II serta harga yang diterima pedagang pengecer pada saluran I dan saluran II adalah sama yaitu masing-masing sebesar Rp. 700,- per butir dan Rp. 1.600,- per butir

Biscarboxy-Functionalized Imidazole and Palladium as Highly Active Catalytic System in Protic Solvents: Methanol and Water

The coupling reaction between aryl bromides and boron reagents is efficiently catalyzed by an in situ generated palladium complex obtained from palladium(II) acetate (0.1 mol%) and 1,3-bis(carboxymethyl)imidazole (0.2 mol%). The catalytic system is very active in protic solvents, especially in methanol. Biaryl derivatives have been prepared in good isolated yields (up to >99%), and additionally styrene and stilbene derivatives have also been prepared by means of this protocol.Financial support from the Ministerio de Ciencia e Innovación (MICINN) of Spain (Project Nos. CTQ2007-65218, CTQ2011-24165, Consolider Ingenio 2010 CSD2007-00006), the Generalitat Valenciana (PROMETEO/2009/039 and FEDER), and the Universidad de Alicante is acknowledged