REPRESENTASI DALAM PEMBELAJARAN MATEMATIKA SISWA KELAS VII MATERI HIMPUNAN SMPK WIGNYA MANDALA TUMPANG

ABSTRAK. Kemampuan representasi merupakan salah satu kemampuan yang mempunyai keterkaitan dengan pemahaman matematika, representasi merupakan hal terpenting dalam mengkonstruksi ide dan pemahaman siswa terkait dengan konsep-konsep matematika. Subjek dalam penelitian ini adalah seluruh siswa kelas VII SMPK Wignya Mandala Tumpang sebanyak 18 siswa akan tetapi hanya 3 subjek yang dinalisis. Pengambilan subjek dalam penelitian ini menggunakan teknik kualitatif berdasarkan representasi kesalahan siswa. Subjek dipilih terlebih dahuluh berdasarkan pertimbangan-pertimbangan peneliti sesuai tujuan penelitian,itu subjek diambil secara acak. Berdasarkan hasil penelitian yang diperoleh menunjukkan jenis-jenis representasi dalam pembelajaran matematika, kesulitan yang berkaitan dengan kesulitan tiga objek menentukan, membaca, dan membedakan. Presentase representasi kesulitan siswa menentukan sebesar 62,0% di kategorikan sedang, kesulitan membaca sebesar 29,% di kategorikan rendah dan kesulitan membedakan sebesar 72,2%) kategori tinggi. faktor penyebabnya kesalahan representasi kemampuan siswa yaitu sulit dalam membedakan bilangan asli, kurang dari serta sulit dalam menentukan irisan, dan dalam menggambar diagram venn, dari kesalahan tersebut siswa tidak dapat menentukan himpunan penyelesaian atau siswa tersebut kesulitan dalam memahami dan mencermati

Market design for a high-renewables European electricity system

This paper presents a set of policy recommendations for the market design of a future European electricity system characterized by a dominant share of intermittent renewable energy supply (RES), in line with the stated targets of European governments. We discuss the market failures that need to be addressed to accommodate RES in liberalized electricity markets, review the evolution of the EU’s RES policy mechanisms, and summarize the key market impacts of RES to date. We then set out economic principles for wholesale market design and use these to develop our policy recommendations. Our analysis covers the value of interconnection and market integration, electricity storage, the design of RES support mechanisms, distributed generation and network tariffs, the pricing of electricity and flexibility as well as long-term contracting and risk management

Parallel Search with no Coordination

We consider a parallel version of a classical Bayesian search problem. $k$ agents are looking for a treasure that is placed in one of the boxes indexed by $\mathbb{N}^+$ according to a known distribution $p$. The aim is to minimize the expected time until the first agent finds it. Searchers run in parallel where at each time step each searcher can "peek" into a box. A basic family of algorithms which are inherently robust is \emph{non-coordinating} algorithms. Such algorithms act independently at each searcher, differing only by their probabilistic choices. We are interested in the price incurred by employing such algorithms when compared with the case of full coordination. We first show that there exists a non-coordination algorithm, that knowing only the relative likelihood of boxes according to $p$, has expected running time of at most $10+4(1+\frac{1}{k})^2 T$, where $T$ is the expected running time of the best fully coordinated algorithm. This result is obtained by applying a refined version of the main algorithm suggested by Fraigniaud, Korman and Rodeh in STOC'16, which was designed for the context of linear parallel search.We then describe an optimal non-coordinating algorithm for the case where the distribution $p$ is known. The running time of this algorithm is difficult to analyse in general, but we calculate it for several examples. In the case where $p$ is uniform over a finite set of boxes, then the algorithm just checks boxes uniformly at random among all non-checked boxes and is essentially $2$ times worse than the coordinating algorithm.We also show simple algorithms for Pareto distributions over $M$ boxes. That is, in the case where $p(x) \sim 1/x^b$ for $0< b < 1$, we suggest the following algorithm: at step $t$ choose uniformly from the boxes unchecked in ${1, . . . ,min(M, \lfloor t/\sigma\rfloor)}$, where $\sigma = b/(b + k - 1)$. It turns out this algorithm is asymptotically optimal, and runs about $2+b$ times worse than the case of full coordination

Correction: Use of "biokitHSV-2 Rapid Assay" to improve the positive predictive value of Focus HerpeSelect HSV-2 ELISA

As the competing interests for only the previous calendar year were included in the published article and it is journal policy to list competing interests for the previous five years, a full declaration of interests for the authors is now published

Cyclic-AMP regulates postnatal development of neural and behavioral responses to NaCl in rats

During postnatal development rats demonstrate an age-dependent increase in NaCl chorda tympani (CT) responses and the number of functional apical amiloride-sensitive epithelial Na+channels (ENaCs) in salt sensing fungiform (FF) taste receptor cells (TRCs). Currently, the intracellular signals that regulate the postnatal development of salt taste have not been identified. We investigated the effect of cAMP, a downstream signal for arginine vasopressin (AVP) action, on the postnatal development of NaCl responses in 19–23 day old rats. ENaC-dependent NaCl CT responses were monitored after lingual application of 8-chlorophenylthio-cAMP (8-CPT-cAMP) under open-circuit conditions and under ±60 mV lingual voltage clamp. Behavioral responses were tested using 2 bottle/24h NaCl preference tests. The effect of [deamino-Cys1, D-Arg8]-vasopressin (dDAVP, a specific V2R agonist) was investigated on ENaC subunit trafficking in rat FF TRCs and on cAMP generation in cultured adult human FF taste cells (HBO cells). Our results show that in 19–23 day old rats, the ENaC-dependent maximum NaCl CT response was a saturating sigmoidal function of 8-CPT-cAMP concentration. 8-CPT-cAMP increased the voltage-sensitivity of the NaCl CT response and the apical Na+ response conductance. Intravenous injections of dDAVP increased ENaC expression and γ-ENaC trafficking from cytosolic compartment to the apical compartment in rat FF TRCs. In HBO cells dDAVP increased intracellular cAMP and cAMP increased trafficking of γ- and δ-ENaC from cytosolic compartment to the apical compartment 10 min post-cAMP treatment. Control 19–23 day old rats were indifferent to NaCl, but showed clear preference for appetitive NaCl concentrations after 8-CPT-cAMP treatment. Relative to adult rats, 14 day old rats demonstrated significantly less V2R antibody binding in circumvallate TRCs. We conclude that an age-dependent increase in V2R expression produces an AVP-induced incremental increase in cAMP that modulates the postnatal increase in TRC ENaC and the neural and behavioral responses to NaCl